refactor(interests): migrate callers to interest_berths junction + drop berth_id

Phase 2b of the berth-recommender refactor (plan §3.4). Every caller of
the legacy `interests.berth_id` column now reads / writes through the
`interest_berths` junction via the helper service introduced in Phase 2a;
the column itself is dropped in a final migration.

Service-layer changes
- interests.service: filter `?berthId=X` becomes EXISTS-against-junction;
  list enrichment uses `getPrimaryBerthsForInterests`; create/update/
  linkBerth/unlinkBerth all dispatch through the junction helpers, with
  createInterest's row insert + junction write sharing a single transaction.
- clients / dashboard / report-generators / search: leftJoin chains pivot
  through `interest_berths` filtered by `is_primary=true`.
- eoi-context / document-templates / berth-rules-engine / portal /
  record-export / queue worker: read primary via `getPrimaryBerth(...)`.
- interest-scoring: berthLinked is now derived from any junction row count.
- dedup/migration-apply + public interest route: write a primary junction
  row alongside the interest insert when a berth is provided.

API contract preserved: list/detail responses still emit `berthId` and
`berthMooringNumber`, derived from the primary junction row, so frontend
consumers (interest-form, interest-detail-header) need no changes.

Schema + migration
- Drop `interestsRelations.berth` and `idx_interests_berth`.
- Replace `berthsRelations.interests` with `interestBerths`.
- Migration 0029_puzzling_romulus drops `interests.berth_id` + the index.
- Tests that previously inserted `interests.berthId` now seed a primary
  junction row alongside the interest.

Verified: vitest 995 passing (1 unrelated pre-existing flake in
maintenance-cleanup.test.ts), tsc clean.

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

src/lib/services/eoi-context.ts

@@ -9,6 +9,7 @@ import { ports } from '@/lib/db/schema/ports';
 import { yachts } from '@/lib/db/schema/yachts';
 import { getCountryName } from '@/lib/i18n/countries';
 import { NotFoundError, ValidationError } from '@/lib/errors';
+import { getPrimaryBerth } from '@/lib/services/interest-berths.service';
 
 // ─── Types ────────────────────────────────────────────────────────────────────
 
@@ -96,6 +97,11 @@ export async function buildEoiContext(interestId: string, portId: string): Promi
     throw new NotFoundError('Interest');
   }
 
+  // Resolve the interest's primary berth via the junction (plan §3.4).
+  // EOI Section 3 stays blank when no primary is set.
+  const primaryBerth = await getPrimaryBerth(interest.id);
+  const primaryBerthId = primaryBerth?.berthId ?? null;
+
   // Parallelise independent reads. Yacht and berth are both nullable -
   // the EOI's Section 3 stays blank when they're absent.
   const [yacht, berth, client, port] = await Promise.all([
@@ -104,9 +110,9 @@ export async function buildEoiContext(interestId: string, portId: string): Promi
           where: and(eq(yachts.id, interest.yachtId), eq(yachts.portId, portId)),
         })
       : Promise.resolve(undefined),
-    interest.berthId
+    primaryBerthId
       ? db.query.berths.findFirst({
-          where: and(eq(berths.id, interest.berthId), eq(berths.portId, portId)),
+          where: and(eq(berths.id, primaryBerthId), eq(berths.portId, portId)),
         })
       : Promise.resolve(undefined),
     db.query.clients.findFirst({