feat: Implement latency profiling and guardrails for performance monitoring

- Added synthetic latency profiler scenarios and CLI scripts for baseline generation and regression checks.
- Introduced latency baseline and threshold artifacts for CI enforcement.
- Enhanced CI workflow with latency guardrail checks.
- Updated documentation to include latency profiling commands and performance metrics.
- Added unit tests for latency guardrail evaluation.

.gitea/workflows/ci.yml

@@ -43,6 +43,13 @@ jobs:
       - name: Tests
         run: pytest -q
 
+      - name: Latency guardrails
+        run: |
+          python scripts/check_latency_regression.py \
+            --baseline ops/performance/latency_baseline.json \
+            --thresholds ops/performance/latency_thresholds.json \
+            --iterations 600
+
       - name: Login to Gitea registry
         if: github.event_name != 'pull_request'
         uses: docker/login-action@v3