feat(editor): add experimental feature adapter panel to AFFiNE canary (#12489)

Closes: [BS-2539](https://linear.app/affine-design/issue/BS-2539/为-affine-添加-ef，并且支持在-affine-预览对应的功能)

> [!warning]
> This feature is only available in the canary build and is intended for debugging purposes.

<!-- This is an auto-generated comment: release notes by coderabbit.ai -->
## Summary by CodeRabbit

- **New Features**
  - Introduced an "Adapter Panel" feature with a new sidebar tab for previewing document content in multiple formats (Markdown, PlainText, HTML, Snapshot), controllable via a feature flag.
  - Added a fully integrated adapter panel component with reactive UI elements for selecting adapters, toggling HTML preview modes, and updating content.
  - Provided a customizable adapter panel for both main app and playground environments, supporting content transformation pipelines and export previews.
  - Enabled seamless toggling and live updating of adapter panel content through intuitive menus and controls.

- **Localization**
  - Added English translations and descriptive settings for the Adapter Panel feature.

- **Chores**
  - Added new package and workspace dependencies along with TypeScript project references to support the Adapter Panel modules and components.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

blocksuite/affine/fragments/adapter-panel/package.json

@@ -0,0 +1,39 @@
+{
+  "name": "@blocksuite/affine-fragment-adapter-panel",
+  "description": "Adapter panel fragment for BlockSuite.",
+  "type": "module",
+  "scripts": {
+    "build": "tsc"
+  },
+  "sideEffects": false,
+  "keywords": [],
+  "author": "toeverything",
+  "license": "MIT",
+  "dependencies": {
+    "@blocksuite/affine-components": "workspace:*",
+    "@blocksuite/affine-ext-loader": "workspace:*",
+    "@blocksuite/affine-model": "workspace:*",
+    "@blocksuite/affine-shared": "workspace:*",
+    "@blocksuite/global": "workspace:*",
+    "@blocksuite/icons": "^2.2.12",
+    "@blocksuite/std": "workspace:*",
+    "@blocksuite/store": "workspace:*",
+    "@floating-ui/dom": "^1.6.13",
+    "@lit/context": "^1.1.2",
+    "@preact/signals-core": "^1.8.0",
+    "@toeverything/theme": "^1.1.14",
+    "lit": "^3.2.0",
+    "rxjs": "^7.8.1"
+  },
+  "exports": {
+    ".": "./src/index.ts",
+    "./view": "./src/view.ts"
+  },
+  "files": [
+    "src",
+    "dist",
+    "!src/__tests__",
+    "!dist/__tests__"
+  ],
+  "version": "0.21.0"
+}