ci: increase integration test timeouts (#1008)

## Summary
- Increase **LLVM Concrete Tests** timeout from 20 → 30 minutes
- Increase **Haskell Proofs** timeout from 60 → 120 minutes

The Haskell Proofs job timed out at ~63% completion in PR #1007, and
LLVM Concrete Tests also hit the 20-minute limit. The timeouts were set
too tight for the current test suite size, especially after recent
additions of float, ptr-cast, transmute, and volatile tests. These
increases provide headroom for runner variability.

## Test plan
- [ ] CI passes on this PR (only workflow file changed)
- [ ] PR #1007 rebased on this branch no longer times out

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

Author: Stevengre

.github/workflows/test.yml

@@ -61,7 +61,7 @@ jobs:
           - name: 'LLVM Concrete Tests'
             test-args: '-k "llvm or test_run_smir_random"'
             parallel: 12
-            timeout: 20
+            timeout: 30
           - name: 'Haskell Exec SMIR'
             test-args: '-k "test_exec_smir and haskell"'
             parallel: 6
@@ -73,7 +73,7 @@ jobs:
           - name: 'Haskell Proofs'
             test-args: '-k "test_prove and not test_prove_termination"'
             parallel: 6
-            timeout: 60
+            timeout: 120
           - name: 'Remainder'
             test-args: '-k "not llvm and not test_run_smir_random and not test_exec_smir and not test_prove_termination and not test_prove"'
             parallel: 6