refactor: deduplicate modals, notifications, confirms, comboboxes, proficiency

Modal Overlay (Finding 1 — 6 admin files):
- Migrated CountriesClient, ManagementLevelsClient, OrgUnitsClient,
  CalculationRulesClient, UtilizationCategoriesClient, RoleModal
  from inline fixed-overlay to AnimatedModal component
- Gains: animated transitions, backdrop blur, escape key for free

Notification Helper (Finding 9 — 9 API files, 14 call sites):
- New createNotification() + createNotificationsForUsers() in
  packages/api/src/lib/create-notification.ts
- Handles exactOptionalPropertyTypes spread + SSE emit internally
- Simplified: budget-alerts, estimate-reminders, auto-staffing,
  vacation-conflicts, chargeability-alerts, comment, vacation, notification

ConfirmDialog (Finding 3 — 11 files):
- Replaced all window.confirm() calls with ConfirmDialog component
- Files: CommentThread, EffortRules, ExperienceMultipliers,
  ManagementLevels, CalculationRules, Countries, RateCards,
  ApplyEffortRules, ApplyExperienceMultipliers, NotificationCenter,
  ReminderModal

EntityCombobox (Finding 4 — 3 files):
- New generic EntityCombobox<T> with customization hooks
- ResourceCombobox + ProjectCombobox rewritten as thin wrappers
- All consumers unchanged (backwards-compatible props)

Proficiency Constants (Finding 2 — 2 files):
- SkillsAnalytics + SkillMarketplace now import from skills/shared.tsx
- Deleted ~70 LOC of local duplicate definitions

Regression: 283 engine + 37 staffing tests pass. TypeScript clean.
AI Assistant: all 87 tools verified accessible.

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

apps/web/src/components/comments/CommentThread.tsx

@@ -3,6 +3,7 @@
 import { useState } from "react";
 import { clsx } from "clsx";
 import { trpc } from "~/lib/trpc/client.js";
+import { ConfirmDialog } from "~/components/ui/ConfirmDialog.js";
 import { CommentInput } from "./CommentInput.js";
 
 interface CommentAuthor {
@@ -118,6 +119,7 @@ function SingleComment({
   isReply?: boolean;
 }) {
   const [showReplyInput, setShowReplyInput] = useState(false);
+  const [confirmDelete, setConfirmDelete] = useState(false);
   const utils = trpc.useUtils();
 
   const createMutation = trpc.comment.create.useMutation({
@@ -199,11 +201,7 @@ function SingleComment({
             )}
             <button
               type="button"
-              onClick={() => {
-                if (window.confirm("Delete this comment?")) {
-                  deleteMutation.mutate({ id: comment.id });
-                }
-              }}
+              onClick={() => setConfirmDelete(true)}
               disabled={deleteMutation.isPending}
               className="text-xs text-gray-400 hover:text-rose-600 dark:hover:text-rose-400"
             >
@@ -236,6 +234,20 @@ function SingleComment({
         </div>
       </div>
 
+      {confirmDelete && (
+        <ConfirmDialog
+          title="Delete comment"
+          message="Are you sure you want to delete this comment?"
+          confirmLabel="Delete"
+          variant="danger"
+          onConfirm={() => {
+            deleteMutation.mutate({ id: comment.id });
+            setConfirmDelete(false);
+          }}
+          onCancel={() => setConfirmDelete(false)}
+        />
+      )}
+
       {/* Render replies */}
       {"replies" in comment && comment.replies.length > 0 && (
         <div className="mt-3 space-y-3 border-l-2 border-gray-100 dark:border-gray-700 pl-2">