refactor(code-review): rename SUCCESS METRICS to COMPLETION CHECKLIST

Correct terminology:
- "Metrics" implies quantitative measurement
- These are actually pass/fail criteria for step completion
- Section is self-validation checklist, not measurement data

Reframe as checkpoint before proceeding to next step:
- Add "Before proceeding to the next step, verify ALL of the following:"
- Change "If any metric" to "If any item"
- Explicit instruction: "Do NOT proceed to the next step" if checklist fails

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

Co-Authored-By: Claude Haiku 4.5 <noreply@anthropic.com>

src/modules/bmm/workflows/4-implementation/code-review/steps/step-01-load-story.md

@@ -105,7 +105,9 @@ Set `git_discrepancies` with categories:
 
 ---
 
-## SUCCESS METRICS
+## COMPLETION CHECKLIST
+
+Before proceeding to the next step, verify ALL of the following:
 
 - `story_path` identified and loaded
 - `story_key` extracted
@@ -115,7 +117,5 @@ Set `git_discrepancies` with categories:
 - `git_discrepancies` calculated
 - Explicit NEXT directive provided
 
-## FAILURE MODES
+**If any item is not met:** Report to the user immediately and HALT the workflow. Do NOT proceed to the next step.
-
-Failure to meet any SUCCESS METRIC constitutes workflow failure.