Link .claude/CLAUDE.md to AGENTS.md, narrow .gitignore

Claude Code does not read AGENTS.md by default, so add a trivial .claude/CLAUDE.md symlink pointing back to ../AGENTS.md (mirroring e.g. PebbleOS), leaving room for .agents/skills/ later. Narrow the blanket /.claude/ ignore to just the local scratch paths used by agent tooling (.claude/pr-*, .claude/branch-*, .claude/sandbox/), add AGENTS.local.md next to CLAUDE.local.md, and drop the link to the Claude docs.

Co-authored-by: Muse Code (Meta Muse Spark)

Author: ambv

.claude/CLAUDE.md

@@ -0,0 +1 @@
+../AGENTS.md

.gitignore

@@ -178,8 +178,12 @@ Python/frozen_modules/MANIFEST
 /python
 !/Python/
 
-# People's custom https://docs.anthropic.com/en/docs/claude-code/memory configs.
-/.claude/
+# Local AI agent scratch state (per-PR and per-branch notebooks, sandbox
+# experiments) and personal agent overrides, none of which are committed.
+/.claude/pr-*
+/.claude/branch-*
+/.claude/sandbox/
+AGENTS.local.md
 CLAUDE.local.md
 
 #### main branch only stuff below this line, things to backport go above. ####