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/server/package.json

@@ -57,12 +57,12 @@
   },
   "dependencies": {
     "@agentclientprotocol/sdk": "^0.17.1",
-    "@ai-sdk/openai": "2.0.52",
     "@anthropic-ai/claude-agent-sdk": "^0.2.11",
-    "@deepgram/sdk": "^3.4.0",
     "@getpaseo/highlight": "0.1.62",
     "@getpaseo/relay": "0.1.62",
     "@isaacs/ttlcache": "^2.1.4",
+    "@mariozechner/pi-agent-core": "^0.67.68",
+    "@mariozechner/pi-ai": "^0.67.68",
     "@mariozechner/pi-coding-agent": "^0.67.68",
     "@modelcontextprotocol/sdk": "^1.20.1",
     "@opencode-ai/sdk": "1.2.6",
@@ -72,10 +72,7 @@
     "ajv": "^8.17.1",
     "dotenv": "^17.2.3",
     "express": "^4.18.2",
-    "express-basic-auth": "^1.2.1",
     "fast-deep-equal": "^3.1.3",
-    "fast-uri": "^3.1.0",
-    "mnemonic-id": "^3.2.7",
     "node-pty": "1.2.0-beta.11",
     "onnxruntime-node": "^1.23.0",
     "openai": "^4.20.0",
@@ -88,7 +85,6 @@
     "sherpa-onnx": "1.12.28",
     "sherpa-onnx-node": "1.12.28",
     "strip-ansi": "^7.1.2",
-    "tiny-invariant": "^1.3.3",
     "uuid": "^9.0.1",
     "which": "^5.0.0",
     "ws": "^8.14.2",
@@ -104,7 +100,6 @@
     "@types/ws": "^8.5.8",
     "@vitest/ui": "^3.2.4",
     "cross-env": "^10.1.0",
-    "playwright": "^1.56.1",
     "tsx": "^4.6.0",
     "typescript": "^5.2.2",
     "vitest": "^3.2.4"