feat(plugin): extract opencode-webhooks as a publishable package

[MathurAditya724]

Extracts the github-webhooks plugin from this image-specific repo into a standalone, publishable npm package at packages/opencode-webhooks/. Other OpenCode users can now consume it the same way they consume @loreai/opencode — bun add + add to the plugin: [...] array.

This image's behavior is unchanged. Internal consumption uses a file: dep in opencode-config-package.json so bun install resolves the package into ~/.config/opencode/node_modules/opencode-webhooks/ at build time.

What changed

• New package: packages/opencode-webhooks/ with its own package.json (MIT, peer dep on @opencode-ai/plugin), tsconfig.json, README.md (full config schema + install instructions), LICENSE, and src/ (11 files moved from plugins/github-webhooks/).
• Source moves detected as renames by git — semantic edits per file are minimal:
  • index.ts: import paths flattened (./github-webhooks/X → ./X), default DB path changed from ~/dev/.opencode/github-webhooks.sqlite to ${XDG_DATA_HOME:-~/.local/share}/opencode-webhooks/deliveries.sqlite, type re-exports added so consumers can author config-generators with type safety.
  • All files: log prefix [github-webhooks] → [opencode-webhooks].
  • handler.ts: /healthz response field {plugin: "github-webhooks"} → {plugin: "opencode-webhooks"}. Public API surface change — anyone scripting health checks against this string needs to update.
• Image wiring:
  • opencode-config-package.json declares "opencode-webhooks": "file:./packages/opencode-webhooks". bun.lock regenerated.
  • opencode-user-config.json references the resolved absolute path in its plugin array (matches the existing @loreai/opencode entry).
  • Dockerfile: COPY plugins/ → COPY packages/, comments updated.
  • webhooks.json: explicit db_path: "/home/developer/dev/.opencode/github-webhooks.sqlite" added to preserve the existing dedup history (~1000 entries) on the cutover. Without this, the new XDG default would orphan the existing DB.
• Deletions: plugins/github-webhooks.ts + plugins/github-webhooks/*.ts (all 11 files) — no shim file, package is the single source of truth.
• Plan + README updates: .opencode/plans/extract-webhooks-plugin-package.md documents the design, including a fact-check against OpenCode's plugin docs. Repo README, .env.example updated to point at the new location and explain the new layout.

Testing

• tsc --noEmit clean against the new tsconfig.json (with @opencode-ai/plugin and @types/bun as devDeps).
• bun install clean against the updated opencode-config-package.json (verified by mocking the install in /tmp/; lock file updated).
• jq valid on webhooks.json, opencode-config-package.json, opencode-user-config.json, package.json.
• Container boot test: not run locally yet. The Dockerfile path is exercised by the build pipeline; if bun install fails to resolve the file: dep at image-build time, the build will fail loudly. Worth a smoke test once this lands.

Out of scope (tracked in plan doc)

• npm publishing workflow.
• Decoupling the gh CLI dependency.
• Tests (the original plugin had none; not adding here to keep the diff focused).
• Schema validation for webhooks.json (would be a behavior change).
• Session reuse + event buffering (separate plan doc, separate PR).

After publish to npm

The plan doc captures a follow-up to simplify the image's wiring: drop the file: dep from opencode-config-package.json, replace the absolute file:// URL in opencode-user-config.json with the bare name "opencode-webhooks", drop the COPY packages/ Dockerfile step. OpenCode auto-installs npm-named plugins into ~/.cache/opencode/node_modules/ at startup.