Single-pass agentic review: F1=63.9% (+10pp over baseline)

Replace 3-pass + quick-wins + aggregation with a single comprehensive
agentic review pass that merges the best elements from all passes:
- Pass 1's comprehensive review + language hints
- Pass 2's commonly-missed bug patterns checklist
- Pass 3's deep tool investigation strategy
- Quick-wins' typo/naming/locale patterns

Results on 10 PRs: P=75.0%, R=55.6%, F1=63.9%
vs v10 multi-pass: P=63.6%, R=51.9%, F1=57.1%
vs v9 baseline:    P=50.6%, R=57.7%, F1=53.9%

2.7x faster (7783s vs 21312s) with better scores on every metric.