fix(sync-gbrain): remove the capability-check page file left in the user's repo

Fixes #2503. On worktree-pinned brains `gbrain put` materializes the checked
page as _capability_check_<pid>.md in the current directory (the user's
repo), and `gbrain delete` removes the page but not the file — every
/sync-gbrain run left a stray file in the repo root. The check now deletes
the materialized file explicitly after the page delete.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

sync-gbrain/SKILL.md

@@ -1104,6 +1104,10 @@ if [ -f ~/.gbrain/config.json ] && \
   fi
 fi
 gbrain delete "$SLUG" 2>/dev/null || true
+# #2503: on worktree-pinned brains `gbrain put` can materialize the page as
+# <slug>.md in the CURRENT directory (the user's repo), and `gbrain delete`
+# removes the page, not the file. Remove the litter explicitly.
+rm -f "./${SLUG}.md" 2>/dev/null || true
 ```
 
 Then update CLAUDE.md based on capability state:

sync-gbrain/SKILL.md.tmpl

@@ -336,6 +336,10 @@ if [ -f ~/.gbrain/config.json ] && \
   fi
 fi
 gbrain delete "$SLUG" 2>/dev/null || true
+# #2503: on worktree-pinned brains `gbrain put` can materialize the page as
+# <slug>.md in the CURRENT directory (the user's repo), and `gbrain delete`
+# removes the page, not the file. Remove the litter explicitly.
+rm -f "./${SLUG}.md" 2>/dev/null || true
 ```
 
 Then update CLAUDE.md based on capability state: