QA hardening: security RLS fixes, Flutter 3.47.5 upgrade, UI/validation fixes

Security — enforce write authorization server-side (was UI/RPC-only):
- it_service_requests RLS: block cross-office read/edit + self-approve (QA-015)
- pass_slips RLS: owner can complete but not self-approve (QA-046)
- swap_requests RLS: scope select/update to participants + admin (QA-047)
- storage: tighten it_service_attachments + task_attachments write/delete (QA-027)
- admin_user_management edge function: allow programmers to manage users (QA-016)

Fixes:
- workforce generator "uncovered shifts" false alarms (QA-043/044)
- network-map VLAN + New-location dialog validation, disabled-until-valid (QA-048)
- de-flake time-of-day-dependent dashboard metrics test (QA-045)

Toolchain:
- upgrade to Flutter 3.47.5 / Dart 3.13.4; font_awesome_flutter 11.0.0,
  flutter_quill 11.6.0, pdfrx 2.6.5; clear resulting deprecations (QA-002)

analyze clean; 139 tests pass; web build succeeds. Report + evidence in docs/qa/.

Note: also carries the in-progress Brick model cleanup already present in the
working tree. QA-001 (AI keys public in the build) is deferred by owner decision.

Co-Authored-By: claude-flow <ruv@ruv.net>

lib/utils/snackbar.dart

@@ -29,6 +29,20 @@ ContentType _mapSnackType(SnackType t) {
   }
 }
 
+/// Reduces exception dumps that callers interpolate into messages (e.g.
+/// `'Error: \$e'` → `Error: PostgrestException(message: X, code: …)`) to
+/// just the human-readable `X`, so users never see raw exception syntax.
+@visibleForTesting
+String humanizeErrorText(String text) => text
+    .replaceAllMapped(
+      RegExp(
+        r'\w*Exception\(message: (.*?)(?:, (?:statusCode|code|details|hint|error):.*)?\)$',
+        dotAll: true,
+      ),
+      (m) => m[1]!,
+    )
+    .replaceAll(RegExp(r'\bException: '), '');
+
 /// Core function used by all of the convenience helpers below.
 void showAwesomeSnackBar(
   BuildContext context, {
@@ -49,7 +63,7 @@ void showAwesomeSnackBar(
       padding: const EdgeInsets.symmetric(vertical: 12, horizontal: 8),
       child: AwesomeSnackbarContent(
         title: title,
-        message: message,
+        message: humanizeErrorText(message),
         contentType: _mapSnackType(snackType),
       ),
     ),
@@ -176,7 +190,7 @@ void showAwesomeSnackBarGlobal({
       padding: const EdgeInsets.symmetric(vertical: 12, horizontal: 8),
       child: AwesomeSnackbarContent(
         title: title,
-        message: message,
+        message: humanizeErrorText(message),
         contentType: _mapSnackType(snackType),
       ),
     ),