feat(equipment): server actions + page guard

equipment.ts: registry CRUD (equipment.manage; delete refused once
reservations exist, archive instead), listEquipmentForMembers (active
items with a member_certified flag computed via the service client),
reserveEquipment / cancelReservation as validated service-client writes
that enforce status, no-overlap and the required-certification gate with
an equipment.manage override (and manager booking on a member's behalf),
listEquipmentReservations and getMyReservations. equipment-guard mirrors
the other module guards. Barrel + API_REFERENCE updated.

lib/equipment-guard.ts

@@ -0,0 +1,31 @@
+import { redirect } from 'next/navigation'
+import { createClient } from '@/lib/supabase/server'
+
+// Server-component guard for the /equipment/manage surface. Mirrors the
+// forms/certifications/classes guards: resolve the member, check
+// equipment.manage via the same RPC the RLS uses, redirect non-managers
+// before any data is fetched. The RLS independently enforces this.
+export async function requireEquipmentManagerPage() {
+  const supabase = await createClient()
+  const {
+    data: { user },
+  } = await supabase.auth.getUser()
+  if (!user) redirect('/login')
+
+  const { data: member } = await supabase
+    .from('space_members')
+    .select('id, space_id, role, user_id, display_name')
+    .eq('user_id', user.id)
+    .in('status', ['current', 'unverified', 'late'])
+    .single()
+  if (!member) redirect('/login')
+
+  const { data: allowed } = await supabase.rpc('user_has_permission', {
+    uid: user.id,
+    sid: member.space_id,
+    perm: 'equipment.manage',
+  })
+  if (!allowed) redirect('/dashboard')
+
+  return { supabase, member }
+}