fix(review-loop-run): counts parses count-by-severity block with scope + format branches (2026-09-13 fix, 40/40 tests)

Was live via ~/sbin symlink but never committed. Baseline for bug 5352fe72.

Claude-Session: https://claude.ai/code/session_01G3SkMRBRWXyiGuMGs8WVas

tests/fixtures/review-loop-run/bullet-list.md

@@ -0,0 +1,10 @@
+# Review
+
+Some findings above.
+
+## Summary
+
+- CRITICAL: 0
+- HIGH: 1
+- MEDIUM: 2
+- LOW: 0

tests/fixtures/review-loop-run/heading-numbers.md

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+# Review
+
+## Finding 3 — HTTP 404 on /widgets
+
+### MEDIUM: endpoint returns wrong status
+
+Some prose mentioning 42 and HIGH severity inline that is not a real count.
+
+## Count by severity
+
+| Severity | Count |
+|----------|-------|
+| CRITICAL | 0 |
+| HIGH | 0 |
+| MEDIUM | 1 |
+| LOW | 0 |

tests/fixtures/review-loop-run/inline-bold.md

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+# Review
+
+## Count by severity
+
+CRITICAL: 0. **HIGH**: 2. MEDIUM: 0. LOW: 0.

tests/fixtures/review-loop-run/no-count-block.md

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+# Review
+
+### CRITICAL: auth bypass on /admin
+
+Detailed explanation of the bypass.
+
+### HIGH: missing input validation
+
+Detailed explanation.
+
+### HIGH: race condition in worker pool
+
+Detailed explanation.
+
+No explicit count-by-severity section is present in this file.

tests/fixtures/review-loop-run/table.md

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+# Review
+
+## Count by severity
+
+| Severity | Count |
+|----------|-------|
+| CRITICAL | 0 |
+| HIGH | 0 |
+| MEDIUM | 1 |
+| LOW | 3 |