feat(berths): split Documents tab into Spec + Deal Documents

Berth detail page now has two tabs:
  - Spec: the existing versioned berth-spec PDF surface (current panel,
    version history, parser badge).
  - Deal Documents: NEW. Lists EOIs / contracts / etc. attached to
    interests currently linked to this berth via interest_berths.

New service helper listDealDocumentsForBerth joins documents →
interests → interest_berths with a port_id guard on both sides.
GET /api/v1/berths/[id]/deal-documents wraps it, gated on berths.view.

Read-only — title, type, status badge, and an Open link to the source
interest page. Edits / sends still happen on the interest's own page.
The Spec tab paragraph now points reps to the new Deal Documents tab
instead of telling them to navigate via Interests.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/components/berths/berth-documents-tab.tsx

@@ -164,8 +164,8 @@ export function BerthDocumentsTab({ berthId }: { berthId: string }) {
     <div className="space-y-6">
       <p className="text-sm text-muted-foreground">
         Berth-spec PDF: the dimensional drawing or surveyor sheet for this slip. Versioned so a
-        misparse can be rolled back. For documents tied to a prospect on this berth (EOI, contract,
-        etc.), open the matching deal in the Interests tab.
+        misparse can be rolled back. Deal documents (EOI, contract, etc.) live on the &ldquo;Deal
+        Documents&rdquo; tab.
       </p>
       <Card>
         <CardHeader className="flex flex-row items-center justify-between pb-3">