feat(equipment): admin manage pages + sidebar

/equipment/manage (guarded by equipment.manage) lists equipment with
inline create/edit, status (available/maintenance/retired), an optional
required-certification picker, asset tag, archive/restore and delete
(refused once reservations exist). Sidebar gets a "Manage equipment"
link in the Admin block. Member browse/reserve is the next phase.

app/(app)/equipment/manage/page.tsx

@@ -0,0 +1,25 @@
+import { requireEquipmentManagerPage } from '@/lib/equipment-guard'
+import { EquipmentManageClient } from './equipment-manage-client'
+
+export const dynamic = 'force-dynamic'
+
+export default async function EquipmentManagePage() {
+  const { supabase, member } = await requireEquipmentManagerPage()
+
+  const [{ data: equipment }, { data: certs }] = await Promise.all([
+    supabase
+      .from('equipment')
+      .select('id, name, description, location, status, required_certification_id, asset_tag, is_active')
+      .eq('space_id', member.space_id)
+      .order('is_active', { ascending: false })
+      .order('name', { ascending: true }),
+    supabase
+      .from('certifications')
+      .select('id, name')
+      .eq('space_id', member.space_id)
+      .eq('is_active', true)
+      .order('name', { ascending: true }),
+  ])
+
+  return <EquipmentManageClient initial={equipment ?? []} certs={certs ?? []} />
+}