Kernel rig: the boss root's curvature round gets the rig's 1800 s cap: on the CI runners, 8 cases at a time, its G2 certification passed 600 s (tangency-labs/smlib#96)

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01DtL5M41G8Nua7HvuFPZkmJ

tests/kernel-cases/fillets/cov-fillet-section-curvature-boss-root-r2/expected.json

@@ -12,5 +12,5 @@
  "tolerance": {
   "rel": 1e-07
  },
- "timeout_s": 600
+ "timeout_s": 1800
 }