v3: AI SDK pivot — pi removed, Next.js 16 + AI SDK 7 + AI Elements teacher app

The teaching agent no longer runs on pi. Stack:
- ToolLoopAgent (ai@7) + OpenRouter (OPENROUTER_API_KEY), model via LH_MODEL,
  default anthropic/claude-sonnet-4.5 with reasoning tokens
- quiz/ask_user_question = client-side tools (no server execute): the call
  lands as a typed tool part in input-available state; the card grades via
  src/core/question-core.ts; addToolOutput sends the verdict; the teacher's
  reaction continues the same assistant message
- resume-mid-quiz is free: the pending tool part persists in the transcript
- persistence: one JSON per chat (data/chats/), full UIMessage transcripts,
  saved onFinish (also on abort)
- UI: AI Elements (owned copy-paste components, pruned to the five in use)
  + button-based QuizCard/AnsweredCard (ask answers never graded)
- pi fully removed: TUI, extensions, Fastify+WS server, bridge, custom
  protocol all deleted (recoverable from git history)
- tests: question-core units carry over; chat-flow integration drives
  handleChatRequest with MockLanguageModelV4 (48 tests, zero tokens);
  render smoke tests guard the cards (renderToStaticMarkup)

Carried over unchanged: teacher system prompt, question-core, schema/
ledger/derive/extract pipeline, data model.

tsconfig.json

@@ -1,17 +1,47 @@
 {
-	"compilerOptions": {
-		"target": "ES2022",
-		"module": "NodeNext",
-		"moduleResolution": "NodeNext",
-		"lib": ["ES2022"],
-		"types": ["node"],
-		"strict": true,
-		"noUncheckedIndexedAccess": true,
-		"verbatimModuleSyntax": true,
-		"allowImportingTsExtensions": true,
-		"jsx": "react-jsx",
-		"noEmit": true,
-		"skipLibCheck": true
-	},
-	"include": ["config.ts", "src/**/*.ts", "extensions/core/**/*.ts"]
+  "compilerOptions": {
+    "target": "ES2022",
+    "lib": [
+      "ES2023",
+      "dom",
+      "dom.iterable"
+    ],
+    "module": "esnext",
+    "moduleResolution": "bundler",
+    "jsx": "react-jsx",
+    "strict": true,
+    "noUncheckedIndexedAccess": true,
+    "verbatimModuleSyntax": true,
+    "allowImportingTsExtensions": true,
+    "noEmit": true,
+    "skipLibCheck": true,
+    "esModuleInterop": true,
+    "isolatedModules": true,
+    "resolveJsonModule": true,
+    "incremental": true,
+    "types": [
+      "node"
+    ],
+    "paths": {
+      "@/*": [
+        "./*"
+      ]
+    },
+    "plugins": [
+      {
+        "name": "next"
+      }
+    ],
+    "allowJs": true
+  },
+  "include": [
+    "next-env.d.ts",
+    "**/*.ts",
+    "**/*.tsx",
+    ".next/types/**/*.ts",
+    ".next/dev/types/**/*.ts"
+  ],
+  "exclude": [
+    "node_modules"
+  ]
 }