Add simple extensions release flow support (#8498)

docs/extension-releasing.md

@@ -0,0 +1,78 @@
+# Extension Releasing
+
+Gemini CLI extensions can be distributed as pre-built binaries through GitHub Releases. This provides a faster and more reliable installation experience for users, as it avoids the need to clone the repository and build the extension from source.
+
+## Asset naming convention
+
+To ensure Gemini CLI can automatically find the correct release asset for each platform, you should follow this naming convention. The CLI will search for assets in the following order:
+
+1.  **Platform and Architecture-Specific:** `{platform}.{arch}.{name}.{extension}`
+2.  **Platform-Specific:** `{platform}.{name}.{extension}`
+3.  **Generic:** If only one asset is provided, it will be used as a generic fallback.
+
+- `{name}`: The name of your extension.
+- `{platform}`: The operating system. Supported values are:
+  - `darwin` (macOS)
+  - `linux`
+  - `win32` (Windows)
+- `{arch}`: The architecture. Supported values are:
+  - `x64`
+  - `arm64`
+- `{extension}`: The file extension of the archive (e.g., `.tar.gz` or `.zip`).
+
+**Examples:**
+
+- `darwin.arm64.my-tool.tar.gz` (specific to Apple Silicon Macs)
+- `darwin.my-tool.tar.gz` (for all Macs)
+- `linux.x64.my-tool.tar.gz`
+- `win32.my-tool.zip`
+
+If your extension is platform-independent, you can provide a single generic asset. In this case, there should be only one asset attached to the release.
+
+## Archive structure
+
+The `gemini-extension.json` file must be at the root of the archive.
+
+## Example GitHub Actions workflow
+
+Here is an example of a GitHub Actions workflow that builds and releases a Gemini CLI extension for multiple platforms:
+
+```yaml
+name: Release Extension
+
+on:
+  push:
+    tags:
+      - 'v*'
+
+jobs:
+  release:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v3
+
+      - name: Set up Node.js
+        uses: actions/setup-node@v3
+        with:
+          node-version: '20'
+
+      - name: Install dependencies
+        run: npm ci
+
+      - name: Build extension
+        run: npm run build
+
+      - name: Create release assets
+        run: |
+          npm run package -- --platform=darwin --arch=arm64
+          npm run package -- --platform=linux --arch=x64
+          npm run package -- --platform=win32 --arch=x64
+
+      - name: Create GitHub Release
+        uses: softprops/action-gh-release@v1
+        with:
+          files: |
+            release/darwin.arm64.my-tool.tar.gz
+            release/linux.arm64.my-tool.tar.gz
+            release/win32.arm64.my-tool.zip
+```