chore(flow): ignore local ai dev artifacts

Ignore disposable .ai review, scratch, cache, trace, and generated buckets so local AI-assisted development can lean on .ai/ without polluting git. Document the intended tracked-vs-local split for .ai/ in the repo.

Author: nikivdev

.gitignore

@@ -2,6 +2,14 @@
 .cargo/
 .ai/internal/
 .ai/web/
+.ai/reviews/
+.ai/test/
+.ai/tmp/
+.ai/cache/
+.ai/artifacts/
+.ai/traces/
+.ai/generated/
+.ai/scratch/
 .ai/skills/
 # keep generated skills ignored by default, but track curated flow-default skills
 !.ai/skills/

docs/ai-dev-layout.md

@@ -0,0 +1,39 @@
+# `.ai/` Dev Layout
+
+Use `.ai/` aggressively for local AI-assisted development, but keep the split
+between tracked project intelligence and disposable local artifacts explicit.
+
+Tracked in this repo:
+
+- `.ai/docs/`
+- `.ai/recipes/`
+- `.ai/repos.toml`
+- curated `.ai/skills/` entries that are intentionally committed
+
+Ignored local-dev buckets:
+
+- `.ai/reviews/`
+  - generated PR feedback packets and review snapshots
+- `.ai/test/`
+  - AI scratch tests and local validation files
+- `.ai/tmp/`
+  - throwaway intermediate files
+- `.ai/cache/`
+  - cached derivations or precomputed local state
+- `.ai/artifacts/`
+  - generated outputs worth inspecting locally but not committing
+- `.ai/traces/`
+  - local trace dumps or trace export scratch
+- `.ai/generated/`
+  - one-off generated code/docs that should be promoted elsewhere if kept
+- `.ai/scratch/`
+  - free-form local notes, prompts, and experiments
+
+Rules of thumb:
+
+1. If it is canonical project knowledge, promote it out of the local bucket and
+   track it intentionally.
+2. If it is generated, per-machine, or iteration-only, keep it under one of the
+   ignored buckets above.
+3. Prefer `.ai/` over random top-level temp files so local AI/dev state stays
+   contained and easy to clean up.