Initial scaffold: tooling, plan, task briefs

- pnpm 10 workspace + TypeScript strict + ESLint flat + Prettier
- CLAUDE.md as canonical brief
- docs/tasks/ — 22 task briefs broken out by phase for sub-sessions
- docs/decisions/ — ADR scaffold

Implements task 01 (repo-init).

tsconfig.json

@@ -0,0 +1,29 @@
+{
+  "compilerOptions": {
+    "target": "ES2022",
+    "lib": ["ES2023", "DOM", "DOM.Iterable"],
+    "module": "ESNext",
+    "moduleResolution": "bundler",
+    "resolveJsonModule": true,
+    "esModuleInterop": true,
+    "allowSyntheticDefaultImports": true,
+    "isolatedModules": true,
+    "verbatimModuleSyntax": true,
+    "strict": true,
+    "noUncheckedIndexedAccess": true,
+    "noImplicitOverride": true,
+    "noFallthroughCasesInSwitch": true,
+    "skipLibCheck": true,
+    "forceConsistentCasingInFileNames": true,
+    "allowJs": false,
+    "noEmit": true,
+    "jsx": "preserve",
+    "incremental": true,
+    "baseUrl": ".",
+    "paths": {
+      "@/*": ["src/*"]
+    }
+  },
+  "include": ["src/**/*", "*.ts", "*.mts", "*.cts"],
+  "exclude": ["node_modules", ".next", "dist", "drizzle"]
+}