feat(systems): a System names its files — path patterns stored, validated and matched (milestone 444 step 3, #4756)

A System gains path_patterns: globs relative to the repo root (* within one
directory, ** across any depth, a plain directory covering everything under
it). One service validates them for every door, so the web UI and MCP refuse
the same bad pattern with the same message. systems_for_paths resolves paths
to every active System that covers them, which step 4 (#4757) uses to deliver
an area's rulings when its files are touched.

- schema: systems.path_patterns JSONB NOT NULL default [] (migration 0113)
- service: normalize_path_patterns, path_matches, systems_for_paths
- routes + MCP create_system/update_system accept it; [] clears
- web UI: a Files field in the create and edit forms, patterns on the card
- backup carries it through export and restore
- using-scribe reflex 7: tagging work keeps a System's files current

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

frontend/src/api/systems.ts

@@ -14,6 +14,12 @@ export interface System {
   color: string | null;
   status: "active" | "archived";
   order_index: number;
+  /**
+   * The files that are this area, as globs relative to the repo root: `*`
+   * within one directory, `**` across any depth, a plain directory covering
+   * everything under it. Empty means the area has not named its files.
+   */
+  path_patterns: string[];
   open_issue_count: number;
   created_at: string | null;
   updated_at: string | null;
@@ -39,7 +45,13 @@ export interface CreatedSystem extends System {
 
 export async function createSystem(
   projectId: number,
-  data: { name: string; description?: string; color?: string; canonical_id?: number },
+  data: {
+    name: string;
+    description?: string;
+    color?: string;
+    canonical_id?: number;
+    path_patterns?: string[];
+  },
 ): Promise<CreatedSystem> {
   return apiPost(`/api/projects/${projectId}/systems`, data);
 }
@@ -53,6 +65,7 @@ export async function updateSystem(
     color: string | null;
     status: "active" | "archived";
     order_index: number;
+    path_patterns: string[];
   }>,
 ): Promise<System> {
   return apiPatch(`/api/projects/${projectId}/systems/${systemId}`, data);