refactor(findings): split ALL-FINDINGS.md into per-experiment files

Break the monolithic 3249-line findings file into 29 individual files,
one per experiment. Each file is named YYYY-MM-DD-NN-slug.md for easy
chronological sorting and discovery.

No content changes — purely structural reorganization.

findings/2026-04-26-03-gpt5-times-out-on-complex.md

@@ -0,0 +1,15 @@
+# Finding 3: GPT-5 times out on complex multi-step analytical tasks (confirmed pattern)
+
+**Date:** 2026-04-26
+**Task:** Full PR review of #382 (research document rewrite)
+**How we used it:** pr-review skill — multi-phase (fetch diff, fetch files,
+check CI, analyze against AC, post inline comments, post summary). 7 phases,
+many curl calls to Gitea API, large diff context. Heavy tool-use workflow
+through SAP proxy (adds latency vs direct API). 300s timeout.
+
+- Timed out 3 times at 300s (17, 6, 6 tool calls respectively)
+- Bottleneck was model processing time, not network (~0.3s Gitea API latency)
+- **Takeaway:** Break analytical tasks into focused bounded pieces. Twelve
+  small deep reviews > one rushed big one. The issue isn't GPT-5's analysis
+  quality — it's that multi-phase tool-heavy workflows burn too much time
+  on mechanics. Separate the data gathering from the analysis.