fix: address additional review feedback

- PresetResolver: add fallback to directory scanning when registry is
  empty/corrupted for robustness and backwards compatibility
- PresetRegistry.update(): add guard to prevent injecting installed_at
  when absent in existing entry (mirrors ExtensionRegistry behavior)
- RFC: update extension list example to match actual CLI output format

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: iamaeroplane

extensions/RFC-EXTENSION-SYSTEM.md

@@ -1087,11 +1087,15 @@ List installed extensions in current project.
 $ specify extension list
 
 Installed Extensions:
-  ✓ jira (v1.0.0) - Jira Integration
-    Commands: 3 | Hooks: 2 | Priority: 10 | Status: Enabled
-
-  ✓ linear (v0.9.0) - Linear Integration
-    Commands: 1 | Hooks: 1 | Priority: 10 | Status: Enabled
+  ✓ Jira Integration (v1.0.0)
+     jira
+     Create Jira issues from spec-kit artifacts
+     Commands: 3 | Hooks: 2 | Priority: 10 | Status: Enabled
+
+  ✓ Linear Integration (v0.9.0)
+     linear
+     Create Linear issues from spec-kit artifacts
+     Commands: 1 | Hooks: 1 | Priority: 10 | Status: Enabled
 ```
 
 **Options:**

src/specify_cli/presets.py

@@ -292,9 +292,13 @@ def update(self, pack_id: str, updates: dict):
         existing = self.data["presets"][pack_id]
         # Merge: existing fields preserved, new fields override
         merged = {**existing, **updates}
-        # Always preserve original installed_at
+        # Always preserve original installed_at based on key existence, not truthiness,
+        # to handle cases where the field exists but may be falsy (legacy/corruption)
         if "installed_at" in existing:
             merged["installed_at"] = existing["installed_at"]
+        else:
+            # If not present in existing, explicitly remove from merged if caller provided it
+            merged.pop("installed_at", None)
         self.data["presets"][pack_id] = merged
         self._save()
 
@@ -1488,17 +1492,35 @@ def resolve(
         # Priority 3: Extension-provided templates (sorted by priority — lower number wins)
         if self.extensions_dir.exists():
             registry = ExtensionRegistry(self.extensions_dir)
-            for ext_id, _metadata in registry.list_by_priority():
-                ext_dir = self.extensions_dir / ext_id
-                if not ext_dir.is_dir():
-                    continue
-                for subdir in subdirs:
-                    if subdir:
-                        candidate = ext_dir / subdir / f"{template_name}{ext}"
-                    else:
-                        candidate = ext_dir / f"{template_name}{ext}"
-                    if candidate.exists():
-                        return candidate
+            registered_extensions = registry.list_by_priority()
+
+            # If registry is empty but extension directories exist, fall back to
+            # directory scanning for robustness (handles corrupted/missing registry)
+            if not registered_extensions:
+                # Scan directories alphabetically with implicit priority=10
+                for ext_dir in sorted(self.extensions_dir.iterdir()):
+                    if not ext_dir.is_dir() or ext_dir.name.startswith("."):
+                        continue
+                    for subdir in subdirs:
+                        if subdir:
+                            candidate = ext_dir / subdir / f"{template_name}{ext}"
+                        else:
+                            candidate = ext_dir / f"{template_name}{ext}"
+                        if candidate.exists():
+                            return candidate
+            else:
+                # Use registry-based resolution with priority ordering
+                for ext_id, _metadata in registered_extensions:
+                    ext_dir = self.extensions_dir / ext_id
+                    if not ext_dir.is_dir():
+                        continue
+                    for subdir in subdirs:
+                        if subdir:
+                            candidate = ext_dir / subdir / f"{template_name}{ext}"
+                        else:
+                            candidate = ext_dir / f"{template_name}{ext}"
+                        if candidate.exists():
+                            return candidate
 
         # Priority 4: Core templates
         if template_type == "template":
@@ -1558,18 +1580,35 @@ def resolve_with_source(
 
         if self.extensions_dir.exists():
             ext_registry = ExtensionRegistry(self.extensions_dir)
-            for ext_id, ext_meta in ext_registry.list_by_priority():
-                ext_dir = self.extensions_dir / ext_id
-                if not ext_dir.is_dir():
-                    continue
-                try:
-                    resolved.relative_to(ext_dir)
-                    version = ext_meta.get("version", "?") if ext_meta else "?"
-                    return {
-                        "path": resolved_str,
-                        "source": f"extension:{ext_id} v{version}",
-                    }
-                except ValueError:
-                    continue
+            registered_extensions = ext_registry.list_by_priority()
+
+            if registered_extensions:
+                # Use registry-based attribution
+                for ext_id, ext_meta in registered_extensions:
+                    ext_dir = self.extensions_dir / ext_id
+                    if not ext_dir.is_dir():
+                        continue
+                    try:
+                        resolved.relative_to(ext_dir)
+                        version = ext_meta.get("version", "?") if ext_meta else "?"
+                        return {
+                            "path": resolved_str,
+                            "source": f"extension:{ext_id} v{version}",
+                        }
+                    except ValueError:
+                        continue
+            else:
+                # Fallback: scan directories when registry is empty/corrupted
+                for ext_dir in sorted(self.extensions_dir.iterdir()):
+                    if not ext_dir.is_dir() or ext_dir.name.startswith("."):
+                        continue
+                    try:
+                        resolved.relative_to(ext_dir)
+                        return {
+                            "path": resolved_str,
+                            "source": f"extension:{ext_dir.name} (unregistered)",
+                        }
+                    except ValueError:
+                        continue
 
         return {"path": resolved_str, "source": "core"}