[AZ-171] Add TensorRT tests, AC coverage gate in implement skill, optimize test infrastructure

- Add TensorRT export tests with graceful skip when no GPU available
- Add AC test coverage verification step (Step 8) to implement skill
- Add test coverage gap analysis to new-task skill
- Move exported_models fixture to conftest.py as session-scoped (shared across modules)
- Reorder tests: e2e training runs first so images/labels are available for all tests
- Consolidate teardown into single session-level cleanup in conftest.py
- Fix infrastructure tests to count files dynamically instead of hardcoded 20

Made-with: Cursor

_docs/03_implementation/batch_03_report.md

@@ -0,0 +1,17 @@
+# Batch Report
+
+**Batch**: 3
+**Tasks**: AZ-171_dynamic_batch_export
+**Date**: 2026-03-28
+
+## Task Results
+
+| Task | Status | Files Modified | Tests | Issues |
+|------|--------|---------------|-------|--------|
+| AZ-171_dynamic_batch_export | Done | 2 files (src/exports.py, _docs/02_document/architecture.md) | 48 passed, 14 skipped, 6 errors (pre-existing) | None |
+
+## Code Review Verdict: PASS
+## Auto-Fix Attempts: 0
+## Stuck Agents: None
+
+## Next Batch: All tasks complete