chore: sync local Mosaic changes

bin/mosaic-sync-skills

@@ -121,6 +121,38 @@ link_skill_into_target() {
   ln -s "$skill_path" "$link_path"
 }
 
+is_mosaic_skill_name() {
+  local name="$1"
+  [[ -d "$MOSAIC_SKILLS_DIR/$name" ]] && return 0
+  [[ -d "$MOSAIC_LOCAL_SKILLS_DIR/$name" ]] && return 0
+  return 1
+}
+
+prune_stale_links_in_target() {
+  local target_dir="$1"
+
+  while IFS= read -r -d '' link_path; do
+    local name resolved
+    name="$(basename "$link_path")"
+
+    if is_mosaic_skill_name "$name"; then
+      continue
+    fi
+
+    resolved="$(readlink -f "$link_path" 2>/dev/null || true)"
+    if [[ -z "$resolved" ]]; then
+      rm -f "$link_path"
+      echo "[mosaic-skills] Removed stale broken skill link: $link_path"
+      continue
+    fi
+
+    if [[ "$resolved" == "$MOSAIC_HOME/"* ]]; then
+      rm -f "$link_path"
+      echo "[mosaic-skills] Removed stale retired skill link: $link_path"
+    fi
+  done < <(find "$target_dir" -mindepth 1 -maxdepth 1 -type l -print0)
+}
+
 for target in "${link_targets[@]}"; do
   mkdir -p "$target"
 
@@ -131,6 +163,8 @@ for target in "${link_targets[@]}"; do
     continue
   fi
 
+  prune_stale_links_in_target "$target"
+
   while IFS= read -r -d '' skill; do
     link_skill_into_target "$skill" "$target"
   done < <(find "$MOSAIC_SKILLS_DIR" -mindepth 1 -maxdepth 1 -type d -print0)