feat(N3): Backend respektiert X-Workspace-ID bei Listen — contacts/dms/mail/calendar (#367)

- Core-Resolver resolve_workspace_scope(): Zuweisungs-Check, leere Werte fallen weg; Exemptions System-Admin + workspaces:configure_modules (Editor-Deadlock)
- require_workspace_scope(module_key) FastAPI-Dependency (deps.py)
- expand_folder_scope(): Ordner-Subtree (zyklensicher) für ContactFolder + DMS Folder; scope_uuid_set() fail-closed
- contacts: folder_ids-Subtree + contact_types auf GET /contacts, List-Cache bei aktivem Scope deaktiviert (Cache-Leak-Gefahr)
- dms: folder_ids-Subtree + file_types (semantische Matcher) auf /files, Baum-Reduktion auf /folders
- mail: account_ids auf /mails, /threads, /accounts
- calendar: calendar_ids auf /calendar/entries, /calendars
- Frontend-Defaults: getModuleConfig() im workspaceStore, ContactsList default_saved_view_id, Calendar default_view
- Tests: 21/21 neu (TDD rot→grün), Regression 81 passed, Checker 0, tsc clean, Vitest grün, Build OK

app/plugins/builtins/dms/routes.py

@@ -21,7 +21,7 @@ from sqlalchemy.ext.asyncio import AsyncSession
 from app.core.db import get_db
 from app.core.storage import LocalStorage, get_storage_backend
 from app.core.visibility import apply_visibility_filter, check_single_entity_access
-from app.deps import get_current_user, require_permission
+from app.deps import get_current_user, require_permission, require_workspace_scope
 
 # BUG-018 God-Object-Split: Helper/Konstanten leben jetzt in common.py;
 # Re-Exports sichern Import- und Patch-Kompatibilitaet
@@ -245,8 +245,13 @@ async def get_file(
 async def list_all_files(
     db: AsyncSession = Depends(get_db),
     current_user: dict = Depends(get_current_user),
+    workspace_scope: dict | None = Depends(require_workspace_scope("dms")),
 ):
-    """List all non-deleted files for the current tenant."""
+    """List all non-deleted files for the current tenant.
+
+    Phase N3: applies the active workspace scope (X-Workspace-ID) as a pure
+    AND-restriction — folder subtree + file types. Never a grant.
+    """
     tenant_id = uuid.UUID(current_user["tenant_id"])
     user_id = uuid.UUID(current_user["user_id"])
     is_system_admin = current_user.get("role") == "admin"
@@ -258,9 +263,32 @@ async def list_all_files(
     query = await apply_visibility_filter(
         db, query, "dms_file", DmsFile, user_id, tenant_id, is_system_admin
     )
+
+    # Phase N3: workspace scope filters (folder subtree + file types)
+    if workspace_scope:
+        from app.services.workspace_scope_service import (
+            DMS_FILE_TYPE_MATCHERS,
+            expand_folder_scope,
+        )
+
+        scope_folder_ids = workspace_scope.get("folder_ids")
+        if isinstance(scope_folder_ids, list) and scope_folder_ids:
+            subtree = await expand_folder_scope(db, Folder, scope_folder_ids)
+            query = query.where(DmsFile.folder_id.in_(subtree or set()))
+
     result = await db.execute(query)
     files = result.scalars().all()
 
+    # file_types needs Python-side matching (semantic matchers, not SQL-LIKE)
+    if workspace_scope:
+        from app.services.workspace_scope_service import DMS_FILE_TYPE_MATCHERS
+
+        scope_file_types = workspace_scope.get("file_types")
+        if isinstance(scope_file_types, list) and scope_file_types:
+            matchers = [DMS_FILE_TYPE_MATCHERS[t] for t in scope_file_types if t in DMS_FILE_TYPE_MATCHERS]
+            if matchers:
+                files = [f for f in files if any(m(f.mime_type) for m in matchers)]
+
     return [
         {
             "id": str(f.id),