WP-00: application foundation

Scaffolds the project: Next.js 16 App Router with strict TypeScript,
Prisma 7 on PostgreSQL 16, Tailwind 4, Vitest, Playwright, CI, and a
standalone Docker image that applies migrations on boot.

Makes the no-tracker rule of PLAN.md 3.7 enforceable rather than
stated. A per-request nonce-based CSP names no external origin, a unit
test fails if any network directive gains one, and a second test fails
if a tracking package appears in package.json. The end-to-end test
drives the standalone server the Docker image runs, not `next dev`,
so a proxy matcher that stopped matching could not pass unnoticed.

Environment is validated at import, so a missing DATABASE_URL fails at
boot with a readable message instead of surfacing later as a driver
error mid-export. ENCRYPTION_KEY is checked to be 32 bytes.

Three deviations from the plan, recorded in PLAN.md and README:
Next 16 rather than 15, `proxy.ts` rather than the now-deprecated
`middleware.ts`, and database-backed sessions rather than Auth.js v5,
which is still beta and whose JWTs would make the session revocation
required by compliance item 23 awkward.

Verified locally against PostgreSQL 16: migrations apply, extensions
created, typecheck, lint, 9 unit tests and the end-to-end header test
all pass.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Cr9dkEHwbDgkWPnyGj1Rjv

tests/unit/env.test.ts

@@ -0,0 +1,49 @@
+import { describe, expect, it, vi } from 'vitest';
+
+/**
+ * The env module validates at import, so each case needs a fresh module
+ * registry with process.env set beforehand.
+ */
+async function loadEnv(values: Record<string, string | undefined>) {
+  const previous = { ...process.env };
+  process.env = { ...previous, ...values } as NodeJS.ProcessEnv;
+  try {
+    vi.resetModules();
+    return await import('@/lib/env');
+  } finally {
+    process.env = previous;
+  }
+}
+
+const VALID_KEY = Buffer.alloc(32, 7).toString('base64');
+
+describe('configuration d’environnement', () => {
+  it('accepte une configuration complète', async () => {
+    const { env } = await loadEnv({
+      DATABASE_URL: 'postgresql://user:pass@localhost:5432/planflow',
+      ENCRYPTION_KEY: VALID_KEY,
+      APP_URL: 'https://planflow.example',
+    });
+
+    expect(env.DATABASE_URL).toContain('planflow');
+    expect(env.APP_URL).toBe('https://planflow.example');
+  });
+
+  it('refuse une clé de chiffrement qui ne fait pas 32 octets', async () => {
+    await expect(
+      loadEnv({
+        DATABASE_URL: 'postgresql://user:pass@localhost:5432/planflow',
+        ENCRYPTION_KEY: Buffer.alloc(16, 1).toString('base64'),
+      }),
+    ).rejects.toThrow(/ENCRYPTION_KEY/);
+  });
+
+  it('refuse une URL de base non PostgreSQL', async () => {
+    await expect(
+      loadEnv({
+        DATABASE_URL: 'mysql://user:pass@localhost:3306/planflow',
+        ENCRYPTION_KEY: VALID_KEY,
+      }),
+    ).rejects.toThrow(/DATABASE_URL/);
+  });
+});