feat(blocks): add Mini Program customer service workspace

Add a reusable one-to-one chat workspace modeled on WeChat Mini Program customer-service messages, covering text, image, link, and Mini Program page payloads. Include conversation search, message history, responsive navigation, media resolution, Unicode emoji selection, Lexical plain-text composition, attachments, localized copy, and tests for rendering and send behavior.

packages/blocks/package.json

@@ -11,6 +11,7 @@
     "@base-ui/react": "^1.6.0",
     "@base-ui/utils": "^0.3.1",
     "@floating-ui/utils": "^0.2.12",
+    "@lexical/react": "^0.48.0",
     "@tanstack/react-hotkeys": "^0.10.0",
     "@tanstack/react-query": "^5.101.4",
     "@tanstack/react-router": "^1.170.18",
@@ -18,6 +19,7 @@
     "@workspace/i18n": "workspace:*",
     "@workspace/ui": "workspace:*",
     "cmdk": "^1.1.1",
+    "lexical": "^0.48.0",
     "lucide-react": "^1.27.0",
     "react": "^19.2.6",
     "react-dom": "^19.2.6"