feat(berths): inline spec-PDF preview, manual-pin badge, maintenance module toggle, under-offer popover

Post-cutover UAT batch #3:
- #62 Spec tab renders the current berth spec PDF inline (lazy PdfViewer,
  toggleable, default-open) + explicit download. Interest Documents tab
  already previews/downloads linked deal docs inline (verified).
- #57 Surface berths.status_override_mode through the interest-berths API;
  linked-berth rows show an amber "Pin overrides pitch" badge + corrected
  consequence copy when a berth is specifically-pitched but manually pinned
  (the soft-pin wins on the public map).
- #63 New maintenance-module gate (maintenance_module_enabled, default on):
  registry + admin Settings toggle, maintenance-module.service, port-provider
  useMaintenanceModuleEnabled, layout wiring, buildBerthTabs hides the
  Maintenance tab when off, and both maintenance log routes assert the gate.
- #66 BerthOccupancyChip: >1 competing interest opens a popover listing every
  deal (name + stage + in-EOI/primary + link); single stays a direct link.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/app/api/v1/berths/[id]/maintenance/[logId]/route.ts

@@ -4,12 +4,14 @@ import { withAuth, withPermission } from '@/lib/api/helpers';
 import { parseBody } from '@/lib/api/route-helpers';
 import { updateMaintenanceLogSchema } from '@/lib/validators/berths';
 import { updateMaintenanceLog, deleteMaintenanceLog } from '@/lib/services/berths.service';
+import { assertMaintenanceModuleEnabled } from '@/lib/services/maintenance-module.service';
 import { errorResponse } from '@/lib/errors';
 
 // PATCH /api/v1/berths/[id]/maintenance/[logId]
 export const PATCH = withAuth(
   withPermission('berths', 'edit', async (req, ctx, params) => {
     try {
+      await assertMaintenanceModuleEnabled(ctx.portId);
       const body = await parseBody(req, updateMaintenanceLogSchema);
       const log = await updateMaintenanceLog(params.id!, params.logId!, ctx.portId, body, {
         userId: ctx.userId,
@@ -28,6 +30,7 @@ export const PATCH = withAuth(
 export const DELETE = withAuth(
   withPermission('berths', 'edit', async (_req, ctx, params) => {
     try {
+      await assertMaintenanceModuleEnabled(ctx.portId);
       await deleteMaintenanceLog(params.id!, params.logId!, ctx.portId, {
         userId: ctx.userId,
         portId: ctx.portId,