Phase 0 — NestJS + Zod foundation harness (F1–F8) (#1050)

Co-hosted NestJS app behind the existing Express server via a strangler-fig dispatcher, sharing the same better-sqlite3 connection and JWT httpOnly cookie. Additive and dormant: default routing stays on Express, Nest only serves its own /api/_nest diagnostics until a module opts in.

F1 @trek/shared Zod contract package; F2 Nest bootstrap co-hosted (fall-through, single Dockerfile/port); F3 shared better-sqlite3 provider; F4 JWT cookie auth guard (+ @CurrentUser, admin guard); F5 Zod validation pipe + error-envelope parity; F6 Nest test + coverage gates; F7 per-prefix strangler toggle (env, default Express); F8 CI build/typecheck/test/coverage.

Remaining F4/F6/F8 checklist items (trip-access + permission levels + MFA policy, e2e harness/seed + 80% gate, Nest↔Express parity test, Playwright PR-comment workflow) are tracked on the first consuming module cards (L1/A1/C1).

.github/workflows/test.yml

@@ -8,10 +8,33 @@ on:
     branches: [main, dev]
     paths:
       - 'server/**'
-      - '.github/workflows/test.yml'
       - 'client/**'
+      - 'shared/**'
+      - '.github/workflows/test.yml'
 
 jobs:
+  shared-contracts:
+    name: Shared Contracts (Zod)
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v6
+
+      - uses: actions/setup-node@v6
+        with:
+          node-version: 22
+          cache: npm
+          cache-dependency-path: shared/package-lock.json
+
+      - name: Install dependencies
+        run: cd shared && npm ci
+
+      - name: Typecheck
+        run: cd shared && npm run typecheck
+
+      - name: Run tests
+        run: cd shared && npm test
+
   server-tests:
     name: Server Tests
     runs-on: ubuntu-latest
@@ -28,6 +51,15 @@ jobs:
       - name: Install dependencies
         run: cd server && npm ci
 
+      - name: Build (tsc + tsc-alias -> dist)
+        run: cd server && npm run build
+
+      - name: Typecheck (informational)
+        # Legacy code still has pre-existing type errors; this surfaces them
+        # without blocking the migration. Ratchet to blocking once cleaned up.
+        continue-on-error: true
+        run: cd server && npm run typecheck
+
       - name: Run tests
         run: cd server && npm run test:coverage