fix(refresh): skip _shim-* files in orphan check

[jcasimir]

Problem

generate-shims.sh produces _shim-*.md files in agents/review/ as generated artifacts, not synced content. The orphan check in sync-reviewers.sh flagged every one of them as Orphan: _shim-X.md (not in any configured source) on every sync — ~20 lines of pure noise that made it harder to spot real orphans (e.g., when removing a configured source and wanting to verify cleanup of the files it had been producing).

Fix

Extends the existing _template-reviewer.md skip to a case glob that also matches _shim-*.

   filename=$(basename "$filepath")
-  [ "$filename" = "_template-reviewer.md" ] && continue
+  case "$filename" in
+    _template-reviewer.md|_shim-*) continue ;;
+  esac

Convention: underscore-prefixed files in agents/review/ are internal/generated and excluded from orphan reporting. Matches how _template-reviewer.md was already treated.

Discovery context

Found while cleaning up duplicate orchestrator-as-reviewer sources in reviewer-sources.yaml. Every reviewer sync produced a wall of orphan warnings for the auto-regenerated shim files, drowning the legitimate cleanup signal.

Test plan

• Run bash sync-reviewers.sh <registry> <output-dir> against a directory containing only _shim-*.md files — confirm no orphan warnings emit
• Run against a directory with a real orphan (a .md file from a now-removed source) — confirm the orphan warning still fires

🤖 Generated with Claude Code