Phase 5 Complete: E7 NO-GO confirmed + ChatGPT Pro questionnaire

Summary:
- E7 frozen box prune: -3.20% regression (NO-GO) with clean ENV
- Keep E5-2/E5-4 (NEUTRAL) + E6 (NO-GO) as research boxes
- Regression due to build differences (LTO/layout/alignment), not logic

Results:
- Winning boxes: E4-1 (+3.51%), E4-2 (+21.83%), E5-1 (+3.35%) → adopted
- Frozen boxes: E5-2, E5-4, E6, E7 → kept with ENV gates (doc as assets)
- Phase 5 cumulative progress: +6.43% on MIXED profile

Documentation updates:
- PHASE5_E7_FROZEN_BOX_PRUNE_AB_TEST_RESULTS.md: Final NO-GO record
- PHASE5_E7_FROZEN_BOX_PRUNE_NEXT_INSTRUCTIONS.md: E7 conclusion

Next phase planning:
- PHASE_ML2_CHATGPT_QUESTIONNAIRE_FASTLANE.md: Design consultation template
  - Candidates: dedup new boundaries, PGO/layout optimization feasibility

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

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

CURRENT_TASK.md

@@ -200,6 +200,7 @@
   - `docs/analysis/PHASE5_E6_ENV_SNAPSHOT_SHAPE_AB_TEST_RESULTS.md`
   - `docs/analysis/PHASE5_E7_FROZEN_BOX_PRUNE_NEXT_INSTRUCTIONS.md`
   - `docs/analysis/PHASE5_E7_FROZEN_BOX_PRUNE_AB_TEST_RESULTS.md`
+  - `PHASE_ML2_CHATGPT_QUESTIONNAIRE_FASTLANE.md`
 
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