ci: bump build-and-test timeout 15m -> 30m

Track 2 has been timing out on every push since the ANTLR Postgres
parser + vector support landed. The job now has to pull the larger
pgvector/pgvector:pg16 image (used by the shared Testcontainers
fixture for vector E2E tests), install cargo-tarpaulin, build the
full .NET solution, run the Sync test matrix end-to-end against
real Postgres + SQLite testcontainers, and finally run the Rust
tarpaulin coverage pass — none of which fits in the original 15
minute budget. Recent runs (81dbd35 -> 876e616) all hit the cap and
were killed mid-Sync.Core. 30 minutes restores headroom and matches
the existing 20m budget on the LQL Extension Tests track.

Author: MelbourneDeveloper

.github/workflows/ci.yml

@@ -91,7 +91,11 @@ jobs:
   build-and-test:
     name: Build + LQL / Migration / Sync Tests
     runs-on: ubuntu-latest
-    timeout-minutes: 15
+    # 15min was insufficient since the new ANTLR Postgres parser + vector
+    # support landed: pgvector image pull, cargo-tarpaulin install, full
+    # Sync test matrix, and the new Postgres E2E vector tests push the
+    # job past 15 min consistently. 30 min gives realistic headroom.
+    timeout-minutes: 30
     services:
       postgres:
         image: postgres:16