diff --git a/server/supabase/migrations/20260927000034_cross_device_sync_parity.sql b/server/supabase/migrations/20260927000034_cross_device_sync_parity.sql
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@@ -0,0 +1,512 @@
+-- Desktop ↔ mobile sync parity.
+--
+-- The desktop app keeps a local SQLite copy and mirrors it through
+-- CloudSyncService. Mobile and web read and write Supabase directly. Before this
+-- migration the mirror could not see deletions made on another device, could
+-- not tell whether a desktop write changed a history row that mobile holds
+-- with an expected revision, and could not pull edited meeting memos at all.
+--
+-- 1. sync_tombstones: every owner-scoped delete on a synced table leaves a
+--    tombstone the owner can read, so an offline device applies it later.
+-- 2. history.revision moves on any content change, including writes that do
+--    not send a revision (desktop upserts), so mobile's optimistic
+--    concurrency sees desktop edits.
+-- 3. meeting_memos.updated_at so memo edits are pullable by cursor.
+-- 4. (user_id, updated_at, id) cursor indexes for keyset pagination.
+-- 5. Desktop-facing template upsert/delete RPCs keyed by the client id, built
+--    on the existing revision-checked RPCs.
+-- 6. Realtime for tombstones and devices (remote sign-out of a revoked
+--    desktop).
+
+BEGIN;
+
+-- 1) Tombstones ----------------------------------------------------------------
+-- No foreign key to auth.users on purpose: an account deletion cascades into
+-- the synced tables and fires the tombstone trigger for a user row that is
+-- already gone in the same statement. A foreign key would abort the account
+-- deletion. Orphaned tombstones only carry ids and are pruned below.
+CREATE TABLE IF NOT EXISTS public.sync_tombstones (
+  id          bigserial PRIMARY KEY,
+  user_id     uuid NOT NULL,
+  table_name  text NOT NULL CHECK (table_name IN (
+    'history',
+    'dictionary',
+    'meetings',
+    'meeting_memos',
+    'meeting_documents',
+    'memo_tags',
+    'custom_instructions',
+    'user_templates'
+  )),
+  row_id      uuid NOT NULL,
+  deleted_at  timestamptz NOT NULL DEFAULT clock_timestamp()
+);
+
+CREATE INDEX IF NOT EXISTS idx_sync_tombstones_user_deleted
+  ON public.sync_tombstones(user_id, deleted_at, id);
+
+ALTER TABLE public.sync_tombstones ENABLE ROW LEVEL SECURITY;
+
+DROP POLICY IF EXISTS sync_tombstones_read_own ON public.sync_tombstones;
+CREATE POLICY sync_tombstones_read_own
+  ON public.sync_tombstones FOR SELECT TO authenticated
+  USING (user_id = auth.uid());
+
+REVOKE ALL ON TABLE public.sync_tombstones FROM PUBLIC, anon, authenticated;
+GRANT SELECT ON TABLE public.sync_tombstones TO authenticated;
+REVOKE ALL ON SEQUENCE public.sync_tombstones_id_seq FROM PUBLIC, anon, authenticated;
+
+CREATE OR REPLACE FUNCTION public.record_sync_tombstone_v1()
+RETURNS trigger
+LANGUAGE plpgsql
+SECURITY DEFINER
+SET search_path = pg_catalog, public
+AS $$
+BEGIN
+  INSERT INTO public.sync_tombstones(user_id, table_name, row_id)
+  VALUES (OLD.user_id, TG_TABLE_NAME, OLD.id);
+  RETURN OLD;
+END;
+$$;
+
+REVOKE ALL ON FUNCTION public.record_sync_tombstone_v1() FROM PUBLIC, anon, authenticated;
+
+DO $$
+DECLARE
+  t text;
+BEGIN
+  FOREACH t IN ARRAY ARRAY[
+    'history',
+    'dictionary',
+    'meetings',
+    'meeting_memos',
+    'meeting_documents',
+    'memo_tags',
+    'custom_instructions',
+    'user_templates'
+  ]
+  LOOP
+    EXECUTE format('DROP TRIGGER IF EXISTS record_sync_tombstone_v1 ON public.%I', t);
+    EXECUTE format(
+      'CREATE TRIGGER record_sync_tombstone_v1 AFTER DELETE ON public.%I '
+      'FOR EACH ROW EXECUTE FUNCTION public.record_sync_tombstone_v1()',
+      t
+    );
+  END LOOP;
+END $$;
+
+-- Tombstones older than the retention window are useless to a client whose
+-- cursor is older still: such a client must do a full resync anyway. Rows of
+-- deleted accounts are removed at the same time.
+CREATE OR REPLACE FUNCTION public.prune_sync_tombstones_v1(p_retention interval DEFAULT interval '180 days')
+RETURNS bigint
+LANGUAGE plpgsql
+SECURITY DEFINER
+SET search_path = pg_catalog, public, auth
+AS $$
+DECLARE
+  removed bigint;
+BEGIN
+  DELETE FROM public.sync_tombstones AS tombstone
+  WHERE tombstone.deleted_at < clock_timestamp() - p_retention
+     OR NOT EXISTS (SELECT 1 FROM auth.users AS account WHERE account.id = tombstone.user_id);
+  GET DIAGNOSTICS removed = ROW_COUNT;
+  RETURN removed;
+END;
+$$;
+
+REVOKE ALL ON FUNCTION public.prune_sync_tombstones_v1(interval) FROM PUBLIC, anon, authenticated;
+GRANT EXECUTE ON FUNCTION public.prune_sync_tombstones_v1(interval) TO service_role;
+
+-- 2) history.revision follows content changes -----------------------------------
+-- Mobile updates with `revision = expected + 1` and a revision predicate, so a
+-- write that already moved the revision is left alone. A write that did not
+-- (the desktop mirror upserts full rows) bumps it only when user-visible
+-- content changed, so a re-push of identical content never forces a false
+-- conflict on another device.
+CREATE OR REPLACE FUNCTION public.bump_history_revision_v1()
+RETURNS trigger
+LANGUAGE plpgsql
+SET search_path = ''
+AS $$
+BEGIN
+  IF NEW.revision IS NOT DISTINCT FROM OLD.revision
+     AND (
+       NEW.title,
+       NEW.original_text,
+       NEW.polished_text,
+       NEW.summary_text,
+       NEW.is_favorite,
+       NEW.status,
+       NEW.mode
+     ) IS DISTINCT FROM (
+       OLD.title,
+       OLD.original_text,
+       OLD.polished_text,
+       OLD.summary_text,
+       OLD.is_favorite,
+       OLD.status,
+       OLD.mode
+     ) THEN
+    NEW.revision := OLD.revision + 1;
+  END IF;
+  RETURN NEW;
+END;
+$$;
+
+DROP TRIGGER IF EXISTS bump_history_revision_v1 ON public.history;
+CREATE TRIGGER bump_history_revision_v1
+  BEFORE UPDATE ON public.history
+  FOR EACH ROW EXECUTE FUNCTION public.bump_history_revision_v1();
+
+-- 3) meeting_memos.updated_at ----------------------------------------------------
+ALTER TABLE public.meeting_memos ADD COLUMN IF NOT EXISTS updated_at timestamptz;
+UPDATE public.meeting_memos SET updated_at = created_at WHERE updated_at IS NULL;
+ALTER TABLE public.meeting_memos
+  ALTER COLUMN updated_at SET DEFAULT now(),
+  ALTER COLUMN updated_at SET NOT NULL;
+
+DROP TRIGGER IF EXISTS set_updated_at_meeting_memos ON public.meeting_memos;
+CREATE TRIGGER set_updated_at_meeting_memos
+  BEFORE UPDATE ON public.meeting_memos
+  FOR EACH ROW EXECUTE FUNCTION public.moddatetime();
+
+-- 4) Cursor indexes --------------------------------------------------------------
+CREATE INDEX IF NOT EXISTS idx_history_sync_cursor
+  ON public.history(user_id, updated_at, id);
+CREATE INDEX IF NOT EXISTS idx_dictionary_sync_cursor
+  ON public.dictionary(user_id, updated_at, id);
+CREATE INDEX IF NOT EXISTS idx_meetings_sync_cursor
+  ON public.meetings(user_id, updated_at, id);
+CREATE INDEX IF NOT EXISTS idx_meeting_memos_sync_cursor
+  ON public.meeting_memos(user_id, updated_at, id);
+CREATE INDEX IF NOT EXISTS idx_meeting_documents_sync_cursor
+  ON public.meeting_documents(user_id, updated_at, id);
+CREATE INDEX IF NOT EXISTS idx_custom_instructions_sync_cursor
+  ON public.custom_instructions(user_id, updated_at, id);
+CREATE INDEX IF NOT EXISTS idx_user_templates_sync_cursor
+  ON public.user_templates(user_id, updated_at, id);
+
+-- 5) Client-keyed template sync ---------------------------------------------------
+-- The desktop creates templates offline under its own uuid. These wrappers keep
+-- that id and reuse the revision-checked mobile RPCs for every update/delete
+-- rule (builtin immutability, selection fallback), so there is one mutation
+-- contract per template.
+CREATE OR REPLACE FUNCTION public.sync_upsert_user_template_v1(
+  p_id uuid,
+  p_template_kind text,
+  p_name text,
+  p_description text DEFAULT NULL,
+  p_fields jsonb DEFAULT '[]'::jsonb,
+  p_output_format text DEFAULT NULL,
+  p_system_prompt text DEFAULT NULL
+)
+RETURNS public.user_templates
+LANGUAGE plpgsql
+SECURITY DEFINER
+SET search_path = pg_catalog, public, auth
+AS $$
+DECLARE
+  actor_id uuid := auth.uid();
+  current_template public.user_templates;
+  saved public.user_templates;
+BEGIN
+  IF actor_id IS NULL THEN
+    RAISE EXCEPTION 'authentication_required' USING ERRCODE = '42501';
+  END IF;
+  IF p_id IS NULL THEN
+    RAISE EXCEPTION 'template_id_required' USING ERRCODE = '22023';
+  END IF;
+  IF p_template_kind NOT IN ('dictation', 'meeting_document') THEN
+    RAISE EXCEPTION 'invalid_template_kind' USING ERRCODE = '22023';
+  END IF;
+
+  SELECT * INTO current_template
+  FROM public.user_templates
+  WHERE id = p_id
+  FOR UPDATE;
+
+  IF current_template.id IS NOT NULL THEN
+    IF current_template.user_id <> actor_id THEN
+      RAISE EXCEPTION 'template_not_found' USING ERRCODE = 'P0002';
+    END IF;
+    IF current_template.template_kind <> p_template_kind THEN
+      RAISE EXCEPTION 'template_kind_immutable' USING ERRCODE = '22023';
+    END IF;
+    saved := public.update_user_template_v1(
+      p_id,
+      current_template.revision,
+      p_name,
+      p_description,
+      p_fields,
+      p_output_format,
+      p_system_prompt
+    );
+    RETURN saved;
+  END IF;
+
+  INSERT INTO public.user_templates(
+    id, user_id, template_kind, name, description, fields, output_format,
+    template_type, system_prompt, is_builtin
+  )
+  VALUES (
+    p_id,
+    actor_id,
+    p_template_kind,
+    trim(p_name),
+    nullif(trim(p_description), ''),
+    CASE WHEN p_template_kind = 'dictation' THEN p_fields ELSE '[]'::jsonb END,
+    CASE WHEN p_template_kind = 'dictation' THEN p_output_format ELSE NULL END,
+    CASE WHEN p_template_kind = 'meeting_document' THEN 'custom' ELSE NULL END,
+    CASE WHEN p_template_kind = 'meeting_document' THEN p_system_prompt ELSE NULL END,
+    false
+  )
+  RETURNING * INTO saved;
+
+  RETURN saved;
+END;
+$$;
+
+REVOKE ALL ON FUNCTION public.sync_upsert_user_template_v1(uuid, text, text, text, jsonb, text, text)
+  FROM PUBLIC, anon;
+GRANT EXECUTE ON FUNCTION public.sync_upsert_user_template_v1(uuid, text, text, text, jsonb, text, text)
+  TO authenticated;
+
+-- Deleting a template another device already deleted is success.
+CREATE OR REPLACE FUNCTION public.sync_delete_user_template_v1(p_id uuid)
+RETURNS boolean
+LANGUAGE plpgsql
+SECURITY DEFINER
+SET search_path = pg_catalog, public, auth
+AS $$
+DECLARE
+  actor_id uuid := auth.uid();
+  current_revision bigint;
+BEGIN
+  IF actor_id IS NULL THEN
+    RAISE EXCEPTION 'authentication_required' USING ERRCODE = '42501';
+  END IF;
+
+  SELECT revision INTO current_revision
+  FROM public.user_templates
+  WHERE id = p_id AND user_id = actor_id
+  FOR UPDATE;
+
+  IF current_revision IS NULL THEN
+    RETURN false;
+  END IF;
+
+  RETURN public.delete_user_template_v1(p_id, current_revision);
+END;
+$$;
+
+REVOKE ALL ON FUNCTION public.sync_delete_user_template_v1(uuid) FROM PUBLIC, anon;
+GRANT EXECUTE ON FUNCTION public.sync_delete_user_template_v1(uuid) TO authenticated;
+
+-- 6) Realtime -----------------------------------------------------------------------
+DO $$
+DECLARE
+  t text;
+BEGIN
+  FOREACH t IN ARRAY ARRAY['sync_tombstones', 'devices', 'memo_tags', 'custom_instructions', 'user_templates']
+  LOOP
+    IF NOT EXISTS (
+      SELECT 1
+      FROM pg_publication_tables
+      WHERE pubname = 'supabase_realtime'
+        AND schemaname = 'public'
+        AND tablename = t
+    ) THEN
+      EXECUTE format('ALTER PUBLICATION supabase_realtime ADD TABLE public.%I', t);
+    END IF;
+  END LOOP;
+END $$;
+
+-- 7) Portable archive keeps its v1 shape ---------------------------------------
+-- export_account_portability serialised whole rows with to_jsonb, while the
+-- v1 archive contract (server restore and the mobile parser) accepts an exact
+-- key set. Columns added after the archive was frozen (meetings creation
+-- metadata, meeting_documents template/idempotency, meeting_memos.updated_at
+-- above) made every archive with such rows fail validation. Project each
+-- dataset back onto its v1 keys.
+CREATE OR REPLACE FUNCTION public.export_account_portability()
+RETURNS TABLE (
+  canonical_payload text,
+  checksum text,
+  exported_at timestamptz,
+  row_count integer
+)
+LANGUAGE plpgsql
+SECURITY DEFINER
+SET search_path = ''
+AS $$
+DECLARE
+  current_user_id uuid := auth.uid();
+  payload jsonb;
+  payload_text text;
+  dataset_rows integer;
+  exported_timestamp timestamptz := clock_timestamp();
+BEGIN
+  IF current_user_id IS NULL THEN
+    RAISE EXCEPTION 'authentication_required' USING ERRCODE = '42501';
+  END IF;
+
+  SELECT
+      (SELECT count(*) FROM public.dictionary WHERE user_id = current_user_id)
+    + (SELECT count(*) FROM public.history WHERE user_id = current_user_id)
+    + (SELECT count(*) FROM public.meetings WHERE user_id = current_user_id AND team_id IS NULL)
+    + (
+        SELECT count(*)
+          FROM public.transcripts AS transcript
+          JOIN public.meetings AS meeting ON meeting.id = transcript.meeting_id
+         WHERE meeting.user_id = current_user_id
+           AND meeting.team_id IS NULL
+      )
+    + (
+        SELECT count(*)
+          FROM public.meeting_memos AS memo
+          JOIN public.meetings AS meeting ON meeting.id = memo.meeting_id
+         WHERE memo.user_id = current_user_id
+           AND meeting.user_id = current_user_id
+           AND meeting.team_id IS NULL
+      )
+    + (
+        SELECT count(*)
+          FROM public.meeting_documents AS document
+          JOIN public.meetings AS meeting ON meeting.id = document.meeting_id
+         WHERE document.user_id = current_user_id
+           AND meeting.user_id = current_user_id
+           AND meeting.team_id IS NULL
+      )
+    + (
+        SELECT count(*)
+          FROM public.custom_instructions
+         WHERE user_id = current_user_id
+           AND builtin_key IS NULL
+      )
+    INTO dataset_rows;
+
+  IF dataset_rows > 10000 THEN
+    RAISE EXCEPTION 'export_row_limit_exceeded' USING ERRCODE = '54000';
+  END IF;
+
+  payload := jsonb_build_object(
+    'format', 'd3ro-account-portability',
+    'schema_version', 1,
+    'exported_at', exported_timestamp,
+    'owner_id', current_user_id,
+    'source', 'cloud',
+    'account', jsonb_build_object(
+      'profile', coalesce((
+        SELECT jsonb_build_object(
+          'id', profile.id,
+          'name', profile.name,
+          'avatar_url', profile.avatar_url,
+          'locale', profile.locale,
+          'tier', profile.tier,
+          'created_at', profile.created_at,
+          'updated_at', profile.updated_at
+        )
+        FROM public.profiles AS profile
+        WHERE profile.id = current_user_id
+      ), 'null'::jsonb),
+      'settings', coalesce((
+        SELECT jsonb_build_object(
+          'theme_mode', settings.theme_mode,
+          'locale', settings.locale,
+          'haptic_enabled', settings.haptic_enabled,
+          'auto_polish_enabled', settings.auto_polish_enabled,
+          'preferred_stt_model', settings.preferred_stt_model,
+          'preferred_llm_model', settings.preferred_llm_model,
+          'onboarding_version', settings.onboarding_version,
+          'tutorial_completed_at', settings.tutorial_completed_at,
+          'revision', settings.revision,
+          'updated_at', settings.updated_at
+        )
+        FROM public.user_settings AS settings
+        WHERE settings.user_id = current_user_id
+      ), 'null'::jsonb),
+      'subscription', coalesce((
+        SELECT jsonb_build_object(
+          'tier', subscription.tier,
+          'provider', subscription.provider,
+          'status', subscription.status,
+          'current_period_start', subscription.current_period_start,
+          'current_period_end', subscription.current_period_end,
+          'cancel_at', subscription.cancel_at,
+          'auto_renewing', subscription.auto_renewing,
+          'updated_at', subscription.updated_at
+        )
+        FROM public.subscriptions AS subscription
+        WHERE subscription.user_id = current_user_id
+      ), 'null'::jsonb)
+    ),
+    'datasets', jsonb_build_object(
+      'dictionary', coalesce((
+        SELECT jsonb_agg(to_jsonb(dictionary) ORDER BY dictionary.created_at, dictionary.id)
+        FROM public.dictionary AS dictionary
+        WHERE dictionary.user_id = current_user_id
+      ), '[]'::jsonb),
+      'history', coalesce((
+        SELECT jsonb_agg(to_jsonb(history) - 'audio_storage_key' ORDER BY history.created_at, history.id)
+        FROM public.history AS history
+        WHERE history.user_id = current_user_id
+      ), '[]'::jsonb),
+      'meetings', coalesce((
+        SELECT jsonb_agg(to_jsonb(meeting) - ARRAY['audio_storage_key', 'language', 'attendees', 'template_id', 'creation_idempotency_key', 'creation_request_hash']::text[] ORDER BY meeting.created_at, meeting.id)
+        FROM public.meetings AS meeting
+        WHERE meeting.user_id = current_user_id
+          AND meeting.team_id IS NULL
+      ), '[]'::jsonb),
+      'transcripts', coalesce((
+        SELECT jsonb_agg(to_jsonb(transcript) ORDER BY transcript.meeting_id, transcript.segment_index, transcript.id)
+        FROM public.transcripts AS transcript
+        JOIN public.meetings AS meeting ON meeting.id = transcript.meeting_id
+        WHERE meeting.user_id = current_user_id
+          AND meeting.team_id IS NULL
+      ), '[]'::jsonb),
+      'meeting_memos', coalesce((
+        SELECT jsonb_agg(to_jsonb(memo) - 'updated_at' ORDER BY memo.meeting_id, memo.timestamp_ms, memo.id)
+        FROM public.meeting_memos AS memo
+        JOIN public.meetings AS meeting ON meeting.id = memo.meeting_id
+        WHERE memo.user_id = current_user_id
+          AND meeting.user_id = current_user_id
+          AND meeting.team_id IS NULL
+      ), '[]'::jsonb),
+      'meeting_documents', coalesce((
+        SELECT jsonb_agg(to_jsonb(document) - ARRAY['template_id', 'generation_idempotency_key']::text[] ORDER BY document.meeting_id, document.created_at, document.id)
+        FROM public.meeting_documents AS document
+        JOIN public.meetings AS meeting ON meeting.id = document.meeting_id
+        WHERE document.user_id = current_user_id
+          AND meeting.user_id = current_user_id
+          AND meeting.team_id IS NULL
+      ), '[]'::jsonb),
+      'custom_instructions', coalesce((
+        SELECT jsonb_agg(to_jsonb(instruction) ORDER BY instruction.sort_order, instruction.created_at, instruction.id)
+        FROM public.custom_instructions AS instruction
+        WHERE instruction.user_id = current_user_id
+          AND instruction.builtin_key IS NULL
+      ), '[]'::jsonb)
+    ),
+    'exclusions', jsonb_build_array(
+      'raw_audio',
+      'storage_objects',
+      'payment_credentials',
+      'push_tokens'
+    )
+  );
+
+  payload_text := payload::text;
+  IF octet_length(payload_text) > 5242880 THEN
+    RAISE EXCEPTION 'export_payload_too_large' USING ERRCODE = '54000';
+  END IF;
+
+  RETURN QUERY SELECT
+    payload_text,
+    encode(extensions.digest(convert_to(payload_text, 'UTF8'), 'sha256'), 'hex'),
+    exported_timestamp,
+    dataset_rows;
+END;
+$$;
+
+COMMIT;