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).

knip.json

@@ -30,30 +30,14 @@
         "vitest.config.{ts,js}"
       ],
       "project": ["**/*.{ts,tsx,js,jsx}"],
-      "ignore": [
-        "android/**",
-        "ios/**",
-        ".expo/**",
-        "dist/**",
-        "scripts/reset-project.js"
-      ]
+      "ignore": ["android/**", "ios/**", ".expo/**", "dist/**", "scripts/reset-project.js"]
     },
     "packages/cli": {
-      "entry": [
-        "src/index.ts",
-        "bin/paseo",
-        "src/**/*.test.{ts,tsx}",
-        "tests/**/*.{ts,tsx}"
-      ],
+      "entry": ["src/index.ts", "bin/paseo", "src/**/*.test.{ts,tsx}", "tests/**/*.{ts,tsx}"],
       "project": ["src/**/*.{ts,tsx}", "tests/**/*.{ts,tsx}"]
     },
     "packages/relay": {
-      "entry": [
-        "src/index.ts",
-        "src/e2ee.ts",
-        "src/cloudflare-adapter.ts",
-        "src/**/*.test.ts"
-      ],
+      "entry": ["src/index.ts", "src/e2ee.ts", "src/cloudflare-adapter.ts", "src/**/*.test.ts"],
       "project": ["src/**/*.ts"]
     },
     "packages/website": {
@@ -84,7 +68,9 @@
     "get-port-cli",
     "patch-package",
     "cross-env",
-    "expo-module-scripts"
+    "expo-module-scripts",
+    "buffer",
+    "metro-config"
   ],
   "ignoreBinaries": [
     "expo-module",