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/queue/workers/ai.ts

@@ -31,13 +31,13 @@ async function generateEmailDraft(payload: GenerateEmailDraftPayload): Promise<D
   const { db } = await import('@/lib/db');
   const { interests } = await import('@/lib/db/schema/interests');
   const { clients } = await import('@/lib/db/schema/clients');
-  const { berths } = await import('@/lib/db/schema/berths');
   const { interestNotes } = await import('@/lib/db/schema/interests');
   const { emailThreads } = await import('@/lib/db/schema/email');
+  const { getPrimaryBerth } = await import('@/lib/services/interest-berths.service');
   const { and, eq, desc } = await import('drizzle-orm');
 
-  // Fetch interest, client, berth - both lookups port-scoped so a
-  // crafted job payload cannot exfiltrate foreign-tenant data.
+  // Fetch interest, client - both lookups port-scoped so a crafted job
+  // payload cannot exfiltrate foreign-tenant data.
   const [interest, client] = await Promise.all([
     db.query.interests.findFirst({
       where: and(eq(interests.id, interestId), eq(interests.portId, portId)),
@@ -51,13 +51,9 @@ async function generateEmailDraft(payload: GenerateEmailDraftPayload): Promise<D
     throw new Error('Interest or client not found');
   }
 
-  let berthMooring: string | null = null;
-  if (interest.berthId) {
-    const berth = await db.query.berths.findFirst({
-      where: eq(berths.id, interest.berthId),
-    });
-    berthMooring = berth?.mooringNumber ?? null;
-  }
+  // Berth mooring resolved via the interest_berths junction (plan §3.4).
+  const primaryBerth = await getPrimaryBerth(interestId);
+  const berthMooring = primaryBerth?.mooringNumber ?? null;
 
   // Fetch last 5 notes
   const recentNotes = await db