Add web UI with Smokey's crow as the stand-in mascot

- ui/: Vite + plain TypeScript, builds into ./web for `crows serve`
- CrowView mirrors CrowModel in RIVE_CONTRACT.md (pose, trust,
  reactions) so the .riv can replace the SVG later
- Event handling follows the contract's mapping table; server text
  is only ever inserted as text
- Prank: toast plus a send-button cooldown countdown
- art/crow.svg: source art for Rive import

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01UQnSw4RRWp8uqpj3nsnnXF

ui/package.json

@@ -0,0 +1,13 @@
+{
+  "name": "so-many-crows-ui",
+  "private": true,
+  "type": "module",
+  "scripts": {
+    "dev": "vite",
+    "build": "tsc --noEmit && vite build"
+  },
+  "devDependencies": {
+    "typescript": "^5.6.0",
+    "vite": "^6.0.0"
+  }
+}