feat(release): ship an install path that needs no code-signing certificate

Installers could not be published at all: the signing certificate does not
exist yet, and the release pipelines stop at their signing guard. Users had no
way to install a fixed build, so the product was effectively stuck behind a
certificate that takes weeks to obtain.

There is also a second, independent blocker: the download feed sits behind
Cloudflare, which rejects any upload body over about 100 MiB, and the app with
its speech engine exceeds that even when signed.

A portable channel now publishes what can actually be delivered today: the app
compressed into 95 MiB 7z volumes (162 MiB total instead of 243 MiB), a Scoop
bucket for a normal install and uninstall experience, and a verifiable manual
installer script. It is deliberately separate from the auto-update feed, needs
no certificate, and refuses to overwrite an already published version.

bucket/d3ro-voice.json

@@ -0,0 +1,38 @@
+{
+  "version": "1.3.0",
+  "description": "로컬 AI 음성 어시스턴트 (faster-whisper + Ollama, 100% 오프라인 지원)",
+  "homepage": "https://d3ro.chanpaca.net",
+  "license": "MIT",
+  "architecture": {
+    "64bit": {
+      "url": [
+        "https://git.chanpaca.net/api/packages/yunchan/generic/d3ro-voice/portable-1.3.0/D3RO-Voice-1.3.0-x64-portable.7z.001",
+        "https://git.chanpaca.net/api/packages/yunchan/generic/d3ro-voice/portable-1.3.0/D3RO-Voice-1.3.0-x64-portable.7z.002"
+      ],
+      "hash": [
+        "c4824bd625a2f0fd685f6fd3dd8521f4ced7d46954b59f0c10efcd432f82bd3f",
+        "187f4917e53525e736df838b15323e840691d602eadcfd9024407498316932ce"
+      ]
+    }
+  },
+  "shortcuts": [
+    [
+      "D3RO Voice.exe",
+      "D3RO Voice"
+    ]
+  ],
+  "checkver": {
+    "url": "https://git.chanpaca.net/api/packages/yunchan/generic/d3ro-voice/portable-latest/portable.json",
+    "jsonpath": "$.version"
+  },
+  "autoupdate": {
+    "architecture": {
+      "64bit": {
+        "url": [
+          "https://git.chanpaca.net/api/packages/yunchan/generic/d3ro-voice/portable-$version/D3RO-Voice-1.3.0-x64-portable.7z.001",
+          "https://git.chanpaca.net/api/packages/yunchan/generic/d3ro-voice/portable-$version/D3RO-Voice-1.3.0-x64-portable.7z.002"
+        ]
+      }
+    }
+  }
+}