Add PostgreSQL + BRouter to CI E2E tests

CI now runs the full stack for E2E tests:
- PostgreSQL as a service container + schema push via drizzle
- BRouter JAR + Berlin segment (E10_N50) with caching
- Both cached across runs (BRouter JAR + segment)

Removed all skip/workaround logic from tests — all 20 E2E tests
now run in CI with real services.

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

e2e/planner.test.ts

@@ -6,18 +6,6 @@ test.describe("Planner", () => {
     await expect(page).toHaveTitle("trails.cool Planner");
     await expect(page.getByText("Collaborative route planning")).toBeVisible();
   });
-});
-
-// Tests that require PostgreSQL — skip in CI
-test.describe("Planner (requires DB)", () => {
-  test.beforeEach(async ({ request }) => {
-    try {
-      const resp = await request.post("/api/sessions", { data: {} });
-      if (!resp.ok()) test.skip();
-    } catch {
-      test.skip();
-    }
-  });
 
   test("can create a session via API", async ({ request }) => {
     const response = await request.post("/api/sessions", { data: {} });