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/lib/services/interest-berths.service.ts

@@ -143,6 +143,10 @@ export interface InterestBerthWithDetails extends InterestBerth {
   mooringNumber: string | null;
   area: string | null;
   status: string | null;
+  /** Soft-pin marker: when 'manual', the berth's pinned status wins over
+   *  this link's is_specific_interest signal on the public map, so the UI
+   *  warns the rep that "Specifically pitching" won't surface Under Offer. */
+  statusOverrideMode: string | null;
   lengthFt: string | null;
   widthFt: string | null;
   draftFt: string | null;
@@ -169,6 +173,7 @@ export async function listBerthsForInterest(
       mooringNumber: berths.mooringNumber,
       area: berths.area,
       status: berths.status,
+      statusOverrideMode: berths.statusOverrideMode,
       lengthFt: berths.lengthFt,
       widthFt: berths.widthFt,
       draftFt: berths.draftFt,