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/2026-04-26-04-gpt5-defaults-to-delegation-claude.md

@@ -0,0 +1,18 @@
+# Finding 4: GPT-5 defaults to delegation; Claude defaults to doing the work
+
+**Date:** 2026-04-26
+**Task:** PR review delegation to sub-agents
+**How we used them:** Both spawned as sub-agents from main session with
+same task description, same pr-review skill file, same Gitea credentials.
+Difference: GPT-5 got model override to gpt5, Sonnet used default model.
+Both got full skill instructions.
+
+- GPT-5 first attempt: spawned sub-sub-agents and timed out
+- GPT-5 with "do it yourself, no sub-agents" + step-by-step: worked
+- Even with constraints, GPT-5 sometimes dumps raw tool output instead of
+  synthesizing — needs explicit output format instructions
+- Claude (Sonnet/Opus) given the same kind of task does the work directly
+- **Takeaway:** GPT interprets complex task descriptions as delegation
+  opportunities. Claude interprets them as work to do. For GPT: explicit
+  single-actor instructions + output format. For Claude: can give broader
+  mandate. Same skill file, very different behavior.