feat(broker): scaffold apps/broker workspace (bun WS runtime, no port yet)

- @claudemesh/broker package with bun dev/start scripts
- src/index.ts stub: WS server on BROKER_PORT, SIGTERM cleanup
- src/env.ts: Zod-validated env (BROKER_PORT, DATABASE_URL, STATUS_TTL_SECONDS, HOOK_FRESH_WINDOW_SECONDS)
- src/db.ts: re-exports Drizzle client from @turbostarter/db
- src/broker.ts + src/types.ts: placeholders for step 8 port
- README documents run commands, env vars, deploy targets
- tsconfig extends @turbostarter/tsconfig base
- eslint.config.js extends @turbostarter/eslint-config/base

Dependencies declared but not installed yet (ws, drizzle-orm, zod,
libsodium-wrappers + workspace deps). turbo.json unchanged: the global
dev task already has persistent=true + cache=false which is what the
broker needs.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

apps/broker/src/broker.ts

@@ -0,0 +1,12 @@
+// TODO: port from ~/tools/claude-intercom/broker.ts in step 8
+//
+// That implementation carries the battle-tested pieces we'll migrate:
+//   - status_source column (hook > manual > jsonl) + writeStatus rules
+//   - TTL sweeper for stuck-"working" peers
+//   - Pending hook statuses (first-turn race handler)
+//   - /hook/set-status endpoint for Claude Code hook scripts
+//
+// The port swaps SQLite prepared statements for Drizzle queries against
+// the `mesh` pgSchema (see packages/db/src/schema/mesh.ts). All logic
+// and test patterns are ported verbatim — only the persistence layer
+// changes.