refactor(billing): remove Stripe; payments are Payple (web) and Google Play (mobile)

Stripe is not used. Keeping its checkout, portal and webhook paths meant a
second payment provider, a second return-URL format and dead UI.

- Delete the stripe-checkout, stripe-portal and stripe-webhook functions and
  their config; billing-catalog serves Payple prices only, and the web parser
  rejects a catalog that still mixes in Stripe prices.
- Web: drop the Stripe checkout/portal buttons, provider toggle and return
  notices; billing shows Payple only. Past rows with provider='stripe' are
  still displayed ("Stripe (종료)") with a support contact instead of a portal.
- Desktop: delete the Stripe checkout modal, payment IPC channels, preload
  namespace and their types; "Remove ads with Pro" opens the web billing page
  via license.openBilling. Support/refund copy names Payple.
- billingUrl() loses the Stripe-only success/canceled result option; the
  Deno contract is regenerated.
- Migrations and the DB's accepted provider values are untouched (history).
- Docs and the backlog record the removal (MON-04, EXT-STRIPE-01, GAP-BILL-03).

Verified: typecheck (desktop/web/admin/api-client/mobile), contract:check,
deno check all functions, deno test 80/80, desktop 1478/1480 on the Electron
runtime (2 known environment failures), web and admin builds, release
metadata and mobile boundary self-tests, eslint on changed files.

docs/map/03-shared-packages.md

@@ -15,7 +15,7 @@ The canonical place for types and cross-surface logic. Both desktop and web/mobi
 |---|---|---|
 | Types | `./types` | Domain types shared across surfaces |
 | Errors | `./errors` | `D3ROError`, `ErrorCode` |
-| IPC channels | `./ipc-channels` | `IPC_CHANNELS` object + `IPCChannel` union. **SSOT** for every desktop IPC channel (VOICE, AUDIO, STT, TTS, LLM, KEYBINDING, CONFIG, HISTORY, DICTIONARY, WINDOW, SYSTEM, STATS, MEMO, VOICE_COMMAND, CONTEXT, CHAIN, CAPTION, FILE_TRANSCRIPTION, MEETING_SUMMARY, DICTATION_TEMPLATE, VOICE_CONVERSATION, RAG, VOICE_ACTION, MEETING_MODE, MEETING_DOC_TEMPLATE, MEETING_CHAT, LICENSE, CLOUD_SYNC, INSTRUCTION, SYSTEM_AUDIO, POPUP_RESULT, POPUP_HISTORY, POPUP_COMMAND, POPUP_CAPTION, VOICE_PARTIAL, CLIPBOARD, APP, ONLINE_AUTH, ADS, SUPPORT, PAYMENT, INPUT_TELEMETRY, SUGGESTION, POPUP_SUGGESTION) |
+| IPC channels | `./ipc-channels` | `IPC_CHANNELS` object + `IPCChannel` union. **SSOT** for every desktop IPC channel (VOICE, AUDIO, STT, TTS, LLM, KEYBINDING, CONFIG, HISTORY, DICTIONARY, WINDOW, SYSTEM, STATS, MEMO, VOICE_COMMAND, CONTEXT, CHAIN, CAPTION, FILE_TRANSCRIPTION, MEETING_SUMMARY, DICTATION_TEMPLATE, VOICE_CONVERSATION, RAG, VOICE_ACTION, MEETING_MODE, MEETING_DOC_TEMPLATE, MEETING_CHAT, LICENSE, CLOUD_SYNC, INSTRUCTION, SYSTEM_AUDIO, POPUP_RESULT, POPUP_HISTORY, POPUP_COMMAND, POPUP_CAPTION, VOICE_PARTIAL, CLIPBOARD, APP, ONLINE_AUTH, ADS, SUPPORT, INPUT_TELEMETRY, SUGGESTION, POPUP_SUGGESTION) |
 | Key bindings | `./keybinding` | **SSOT** for every global shortcut in the app: `KeyBinding` (`device`/`code`/`ctrl`/`alt`/`shift`/`meta`), `KEY_CATALOG` (10 selectable groups incl. mouse), `KEYBINDING_ACTIONS` (9 rebindable actions incl. the three suggestion actions), `bindingKey`/`normalizeBinding`/`validateBinding`/`detectBindingConflicts`/`formatBindingSegments`/`searchKeyCatalog`/`parseBindingMap`. Persisted as `AppConfig.keyBindings`. i18n keys are exposed as plain `string` so core stays independent of `@d3ro/i18n`; consumers narrow at the boundary (`asTranslationKey`) and a contract test guards the keys — accepted constraint, `11` §7 CONSTRAINT-I18N-01. Tests: `__tests__/keybinding*.test.ts` via `vitest.config.ts` (`npm run test --workspace=@d3ro/core`), 117 cases as of 2026-09-21 |
 | Input intelligence | `./input-intelligence` | **SSOT** for the input-telemetry and next-sentence-suggestion domain (added 2026-09-21): key classification (`classifyKeyStroke`), text metrics (`countWords`/`countSentences`/`endsSentence`/`textBeforeCaret`), `computeTypedDelta` (UIA snapshot diff — the IME-safe way to count typed text), `decideSuggestion` + `isAppExcluded` (when to request / skip / clear), `parseSuggestionCandidates`/`sanitizeSuggestionLine` (prompt-leak and prefix-echo defence), `anchorFloatingPanel` (caret-anchored overlay placement), `mergeActivityBucket`/`summarizeActivity`/`pixelsToMeters`, `extractPhrases`/`selectPhraseHints`, `INPUT_TELEMETRY_DEFAULTS`/`SUGGESTION_DEFAULTS` |
 | Constants | `./constants` | Shared constants |