feat: Sprint A Wahab review batch — categories, property hierarchy, priority grouping

Items 1-5, 9, 11 from denya-wahab-feedback-s2:
- Category.show_in_form (alert-only flag): Gas Leak hidden from issue picker
  but kept urgent for SLA/alert and reporting; emergency quick path on the
  new-issue form creates urgent tickets via include_hidden categories.
- Seed: Aluminum/Glass, Carpentry, Mould & Damp (Medium default) maintenance
  categories; Lost Property renamed Missing Item (+ sub).
- One alembic migration: add show_in_form (backfill True, Gas Leak False) +
  data rename Lost Property -> Missing Item.
- Property -> Building -> Apartment cascade with searchable apartment combobox
  on the new-issue form and ticket list filters; /api/tickets/units gains
  building filter + /units/grouped variant; /api/tickets gains additive
  building/unit_id filters. apartment_mapping.json committed (deterministic).
- Group-by-priority toggle on /tickets (four sections + unknown bucket,
  age-sortable, composes with filters, URL deep links), FM dashboard active
  tickets, and CS dashboard priority card click-through.
- Tests: 13 new (category visibility, seed idempotency/sync, unit grouping,
  ticket building/unit filters).

app/templates/dashboard/fm.html

@@ -127,11 +127,18 @@
 
     <!-- Active Tickets Table -->
     <div class="bg-white rounded-xl shadow-sm border border-gray-200">
-        <div class="px-5 py-4 border-b border-gray-200 flex items-center justify-between">
+        <div class="px-5 py-4 border-b border-gray-200 flex flex-wrap items-center justify-between gap-3">
             <h3 class="text-sm font-semibold text-gray-700 uppercase tracking-wide">Active Tickets</h3>
-            <a href="/tickets" class="text-sm text-denya-600 hover:text-denya-800">View All →</a>
+            <div class="flex items-center space-x-3">
+                <label class="flex items-center space-x-2 text-sm font-medium text-gray-700 cursor-pointer select-none">
+                    <input type="checkbox" x-model="groupByPriority" class="rounded border-gray-300 text-denya-600 focus:ring-denya-500">
+                    <span>Group by priority</span>
+                </label>
+                <button x-show="groupByPriority" @click="ageDir = ageDir === 'asc' ? 'desc' : 'asc'" class="px-2 py-1 text-xs border border-gray-300 rounded-lg hover:bg-gray-50 text-gray-600" x-text="ageDir === 'desc' ? 'Newest first ↓' : 'Oldest first ↑'"></button>
+                <a href="/tickets" class="text-sm text-denya-600 hover:text-denya-800">View All →</a>
+            </div>
         </div>
-        <div class="overflow-x-auto">
+        <div class="overflow-x-auto" x-show="!groupByPriority">
             <table class="w-full text-sm">
                 <thead class="bg-gray-50 text-gray-600 text-xs uppercase tracking-wider">
                     <tr>
@@ -160,6 +167,32 @@
                 </tbody>
             </table>
         </div>
+        <div class="space-y-3 p-3" x-show="groupByPriority">
+            <template x-for="meta in priorityGroupMeta()" :key="meta.key">
+                <div x-show="(groupedActiveTickets[meta.key] || []).length" class="rounded-xl border border-gray-200 overflow-hidden">
+                    <div class="px-4 py-2.5 flex items-center justify-between border-b border-gray-100" :class="meta.cls">
+                        <span class="text-sm font-semibold text-gray-800" x-text="`${meta.label} (${groupedActiveTickets[meta.key].length})`"></span>
+                    </div>
+                    <div class="overflow-x-auto">
+                        <table class="w-full text-sm">
+                            <tbody class="divide-y divide-gray-100">
+                                <template x-for="ticket in groupedActiveTickets[meta.key]" :key="ticket.id">
+                                    <tr class="hover:bg-gray-50 transition cursor-pointer" @click="window.location.href='/tickets/'+ticket.id">
+                                        <td class="px-5 py-3 font-medium text-denya-600" x-text="ticket.ticket_number"></td>
+                                        <td class="px-5 py-3"><span class="px-2 py-1 rounded-full text-xs font-medium" :class="statusClass(ticket.status)" x-text="ticket.status"></span></td>
+                                        <td class="px-5 py-3"><span class="px-2 py-1 rounded text-xs font-medium" :class="priorityClass(ticket.priority)" x-text="priorityBadge(ticket.priority)"></span></td>
+                                        <td class="px-5 py-3 text-gray-600" x-text="ticket.assigned_technician_name || 'Unassigned'"></td>
+                                        <td class="px-5 py-3 text-gray-600 max-w-xs truncate" x-text="ticket.description || ''"></td>
+                                        <td class="px-5 py-3 text-xs font-medium" :class="timeSince(ticket.created_at).includes('d') && parseInt(timeSince(ticket.created_at)) > 3 ? 'text-red-600' : 'text-gray-500'" x-text="timeSince(ticket.created_at)"></td>
+                                    </tr>
+                                </template>
+                            </tbody>
+                        </table>
+                    </div>
+                </div>
+            </template>
+            <div x-show="!activeTickets.length" class="px-5 py-12 text-center text-gray-400">No active tickets</div>
+        </div>
     </div>
 </div>
 
@@ -171,6 +204,12 @@
             aging: {},
             activeTickets: [],
             emergencyCount: 0,
+            groupByPriority: false,
+            ageDir: 'desc',
+
+            get groupedActiveTickets() {
+                return app().groupByPriority(this.activeTickets, this.ageDir);
+            },
 
             async init() {
                 await this.loadData();