Campaign assignments, ownership-based editing, and role-scoped data

- Add campaign_assignments table for user-to-campaign mapping
- Superadmin/managers can assign users to campaigns; visibility filtered by assignment/ownership
- Managers can only manage (tracks, assignments) on campaigns they created
- Budget controlled by superadmin only, with proper modal UI for editing
- Ownership-based editing for campaigns, projects, comments (creators can edit their own)
- Role-scoped dashboard and finance data (managers see only their campaigns' data)
- Manager's budget derived from sum of their campaign budgets set by superadmin
- Hide UI features users cannot use (principle of least privilege across all pages)
- Fix profile completion prompt persisting after saving (login response now includes profileComplete)
- Add post detail modal in campaign detail with thumbnails, publication links, and metadata
- Add comment inline editing for comment authors
- Move financial summary cards below filters on Campaigns page

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

client/src/App.jsx

@@ -59,6 +59,8 @@ function AppContent() {
       // Check if profile is incomplete
       if (!user.profileComplete && user.role !== 'superadmin') {
         setShowProfilePrompt(true)
+      } else {
+        setShowProfilePrompt(false)
       }
     } else if (!authLoading) {
       setLoading(false)