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>

tests/test_guidance_ownership.py

@@ -205,6 +205,9 @@ TOPICS: tuple[Topic, ...] = (
     Topic("code says what a thing does, not what was wanted", U,
           ("rulings", "unconfirmed"),
           "code tells you what a thing does, not what was wanted"),
+    Topic("a System names its files, and tagging work keeps them current", U,
+          ("path_patterns", "update_system"),
+          "which files are which area is your call"),
     # ── process arcs — owned by their skills ──
     Topic("plan in a milestone, steps created together", "skill:writing-plans", ("start_planning", "{{ref:"),
           "a milestone earns its place when the work has an arc", index=("start_planning",)),