fix: increase workspace lib test timeout 25→30 min (cold cache timeout) (#738)

Five-Whys: GitHub badge red on main.
1. Why red? workspace-test failed on main at 10:43
2. Why failed? "timed out after 25 minutes"
3. Why timeout? PR #734 merge triggered fresh compile (no incremental cache)
4. Why no cache? First run on new commit, cold Docker container
5. Root cause: 25-min timeout too tight for cold-cache 75-crate workspace

Fix: Bump to 30 min. Warm cache runs take ~20 min. Cold cache needs ~27 min.

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

Author: noahgift

.github/workflows/ci.yml

@@ -41,7 +41,7 @@ jobs:
       - name: Workspace lib tests (25,300+)
         # Excluded: aprender-gpu (cuBLAS), aprender-cuda-edge (CUDA), aprender-compute (SIMD SIGSEGV at exit)
         run: cargo test --workspace --lib --exclude aprender-gpu --exclude aprender-cuda-edge --exclude aprender-compute
-        timeout-minutes: 25
+        timeout-minutes: 30
       - name: Compute tests (tolerate SIGSEGV at exit — all tests pass but harness crashes on cleanup)
         run: cargo test -p aprender-compute --lib 2>&1 | tee /tmp/compute-test.log; grep -q 'test result.*0 failed' /tmp/compute-test.log
       - name: Integration tests