feat(plugins): 插件市场索引与签名发布流水线

- plugins/registry/<id>.toml 指向作者仓库的固定 commit（repo、commit、path）
- scripts/plugin_registry.py：check 在 PR 上校验改动的条目、运行作者测试、
  从 web-src/ 构建前端并写审查摘要；build 在合并后增量打包（commit 未变的
  条目复用已发布的 zip）
- plugin-registry.yml：check / build 不读 secret，sign 只用 PLUGIN_SIGNING_KEY
  签名，不运行作者代码；发布到 release plugins 并删除下架的资源
- 插件目录改用独立的插件公钥 ab_plugin_pubkey.pem，与在线更新密钥分开
- catalog 条目新增 authors、permissions、has_web、repo、commit、readme
- 6 个示例插件上架；上架文档（中 / 英 / 日）、PR 模板与 CODEOWNERS

.github/CODEOWNERS

@@ -0,0 +1,2 @@
+/plugins/registry/ @EstrellaXD
+/plugins/revoked.toml @EstrellaXD

.github/PULL_REQUEST_TEMPLATE/plugin.md

@@ -0,0 +1,28 @@
+<!-- Plugin listing PR. Base branch: 4.0-dev. Docs: https://autobangumi.org/dev/plugins/publish -->
+
+## Plugin
+
+- id:
+- repo:
+- commit (40-char SHA):
+- New plugin / update (old version -> new version):
+
+## Author checklist
+
+- [ ] This PR changes only files under `plugins/registry/`.
+- [ ] `commit` is a full 40-character SHA, and it is pushed to a public repository.
+- [ ] The file name equals the `id` in `plugin.toml`.
+- [ ] `tests/` has at least 1 test, and all tests pass.
+- [ ] `ab-plugin validate` passes.
+- [ ] For an update, `version` is higher than the listed version, and `repo` is unchanged.
+- [ ] If the plugin has a frontend, its source is in `web-src/` with `package.json` and `pnpm-lock.yaml`.
+- [ ] The plugin depends only on the standard library and packages that AutoBangumi ships. Other pure-Python libraries are in `vendor/`.
+- [ ] I agree that AutoBangumi redistributes the packed plugin in its release.
+
+## Maintainer review checklist
+
+- [ ] I read all code at the compare link (update) or tree link (new plugin) in the Job Summary.
+- [ ] The plugin connects only to documented hosts.
+- [ ] The plugin writes nothing outside `config/`.
+- [ ] If there is a frontend, I read `web-src/` line by line. It runs on the main origin.
+- [ ] The declared `permissions` match what the code does.

.github/workflows/plugin-registry.yml

@@ -0,0 +1,119 @@
+name: Plugin Registry
+
+# 插件市场：plugins/registry/<id>.toml 指向作者仓库的固定 commit。
+# - check：PR 上运行作者的代码（测试、pnpm 构建），所以只读权限、不读任何 secret。
+# - build：合并后打包，同样没有密钥；commit 未变的条目复用已发布的 zip。
+# - sign：只有这个 job 读 PLUGIN_SIGNING_KEY，它不运行作者的任何代码，
+#   只用 build_plugin_catalog.py 读 zip 里的 plugin.toml 并签名。
+on:
+  pull_request:
+    branches: ["4.0-dev"]
+    paths: ["plugins/**", "scripts/plugin_registry.py", ".github/workflows/plugin-registry.yml"]
+  push:
+    branches: ["4.0-dev"]
+    paths: ["plugins/**"]
+  workflow_dispatch:
+
+permissions:
+  contents: read
+
+concurrency:
+  group: plugin-registry-${{ github.event_name == 'pull_request' && github.ref || 'publish' }}
+  cancel-in-progress: false
+
+jobs:
+  check:
+    if: github.event_name == 'pull_request'
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          fetch-depth: 0 # 需要 base 分支上的旧条目
+      - &python
+        uses: actions/setup-python@v5
+        with:
+          python-version: "3.13"
+      - &uv
+        uses: astral-sh/setup-uv@v4
+        with:
+          version: "latest"
+      - &pnpm
+        uses: pnpm/action-setup@v4
+        with:
+          version: 9
+          run_install: false
+      - &node
+        uses: actions/setup-node@v4
+        with:
+          node-version: 20
+      - &deps
+        name: Install backend
+        run: mkdir -p backend/config && cd backend && uv sync --group dev
+      - name: Check changed entries
+        run: |
+          set -o pipefail
+          uv run --project backend python scripts/plugin_registry.py check \
+            --base "origin/${{ github.base_ref }}" --out dist | tee -a "$GITHUB_STEP_SUMMARY"
+
+  build:
+    if: github.event_name != 'pull_request'
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - *python
+      - *uv
+      - *pnpm
+      - *node
+      - *deps
+      - name: Download current catalog
+        env:
+          GH_TOKEN: ${{ github.token }}
+        run: gh release download plugins -p catalog.json -D old || echo "release plugins 还不存在，全部重新打包"
+      - name: Build
+        run: uv run --project backend python scripts/plugin_registry.py build --old old/catalog.json --out dist
+      - uses: actions/upload-artifact@v4
+        with:
+          name: plugins-dist
+          path: dist/
+          retention-days: 7
+
+  sign:
+    needs: build
+    runs-on: ubuntu-latest
+    permissions:
+      contents: write
+    steps:
+      - uses: actions/checkout@v4
+      - uses: astral-sh/setup-uv@v4
+        with:
+          version: "latest"
+      - uses: actions/download-artifact@v4
+        with:
+          name: plugins-dist
+          path: dist
+      - name: Sign catalog
+        env:
+          PLUGIN_SIGNING_KEY: ${{ secrets.PLUGIN_SIGNING_KEY }}
+        run: |
+          if [ -z "$PLUGIN_SIGNING_KEY" ]; then
+            echo "::error::PLUGIN_SIGNING_KEY secret is not set" >&2
+            exit 1
+          fi
+          umask 077
+          printf '%s\n' "$PLUGIN_SIGNING_KEY" > "$RUNNER_TEMP/key.pem"
+          uv run --no-project --with cryptography python scripts/build_plugin_catalog.py \
+            --key "$RUNNER_TEMP/key.pem" --sources dist/sources.json --out release-assets dist/*.zip
+          rm -f "$RUNNER_TEMP/key.pem"
+      - name: Publish
+        env:
+          GH_TOKEN: ${{ github.token }}
+        run: |
+          # tag 名不含 beta / alpha，不会触发 build.yml 的镜像构建
+          gh release view plugins >/dev/null 2>&1 || gh release create plugins \
+            --target "${{ github.sha }}" --latest=false --title "Plugin catalog" \
+            --notes "AutoBangumi 插件市场的签名目录，由 plugin-registry 工作流维护。"
+          gh release upload plugins release-assets/* --clobber
+          # 下架：删除不在新目录中的旧 zip 与签名
+          for asset in $(gh release view plugins --json assets -q '.assets[].name'); do
+            [ -e "release-assets/$asset" ] || gh release delete-asset plugins "$asset" -y
+          done