chore: remove unused deps and declare missing ones

Knip-driven cleanup across all workspaces:

Removed (verified zero imports):
- root: @anthropic-ai/claude-agent-sdk, @modelcontextprotocol/sdk,
  expo, react, react-native, react-dom (duplicates of workspace deps)
- server: @ai-sdk/openai, @deepgram/sdk, express-basic-auth,
  fast-uri, mnemonic-id, tiny-invariant, playwright
- app: @expo/vector-icons, @getpaseo/server,
  @react-navigation/bottom-tabs, @react-navigation/elements,
  base64-js, react-native-css, expo-av, expo-font, expo-symbols,
  expo-web-browser, react-native-permissions,
  react-native-popover-view, react-native-securerandom
- cli: @getpaseo/relay
- desktop: @getpaseo/cli
- relay: @cloudflare/workers-types
- website: tailwindcss (provided by @tailwindcss/vite)

Declared (previously hoisted, now explicit):
- root: @types/ws, playwright, ws (used by scripts/)
- server: @mariozechner/pi-ai, @mariozechner/pi-agent-core
- app: expo-asset, qrcode, @types/qrcode, tiny-invariant,
  @xterm/headless, dotenv, jsdom
- cli: vitest
- desktop: vitest

Also removes the stray `/app.json` (obsolete, overridden by
packages/app/app.config.js).

packages/cli/package.json

@@ -24,7 +24,6 @@
   },
   "dependencies": {
     "@clack/prompts": "^1.0.0",
-    "@getpaseo/relay": "0.1.62",
     "@getpaseo/server": "0.1.62",
     "chalk": "^5.3.0",
     "commander": "^12.0.0",
@@ -37,6 +36,7 @@
     "@types/ws": "^8.5.8",
     "tsx": "^4.6.0",
     "typescript": "^5.2.2",
+    "vitest": "^3.2.4",
     "zx": "^8.8.5"
   }
 }