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>

src/scribe/models/system.py

@@ -1,4 +1,5 @@
-from sqlalchemy import ForeignKey, Index, Integer, Text, UniqueConstraint
+from sqlalchemy import ForeignKey, Index, Integer, Text, UniqueConstraint, text
+from sqlalchemy.dialects.postgresql import JSONB
 from sqlalchemy.orm import Mapped, mapped_column
 
 from scribe.models import Base
@@ -38,6 +39,15 @@ class System(Base, TimestampMixin, SoftDeleteMixin):
     # active | archived — systems accumulate; archive rather than delete.
     status: Mapped[str] = mapped_column(Text, default="active", server_default="active")
     order_index: Mapped[int] = mapped_column(Integer, default=0, server_default="0")
+    # The files that ARE this area, as globs relative to the repo root
+    # (milestone 444). The description says what the area is FOR; these say
+    # where it lives, so a command or edit touching those files can be
+    # resolved to the System — and its rulings — without a similarity search.
+    # NOT NULL with a `[]` default for the reason DesignToken.supersedes gives:
+    # a nullable list has two empties, and every reader must handle both.
+    path_patterns: Mapped[list] = mapped_column(
+        JSONB, nullable=False, default=list, server_default=text("'[]'::jsonb")
+    )
 
     __table_args__ = (
         Index("ix_systems_project_id", "project_id"),
@@ -54,6 +64,7 @@ class System(Base, TimestampMixin, SoftDeleteMixin):
             "color": self.color,
             "status": self.status,
             "order_index": self.order_index,
+            "path_patterns": list(self.path_patterns or []),
             "created_at": iso(self.created_at),
             "updated_at": iso(self.updated_at),
         }