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/clients.service.ts

@@ -12,7 +12,7 @@ import {
 import { companies, companyMemberships } from '@/lib/db/schema/companies';
 import { yachts } from '@/lib/db/schema/yachts';
 import { berthReservations } from '@/lib/db/schema/reservations';
-import { interests } from '@/lib/db/schema/interests';
+import { interests, interestBerths } from '@/lib/db/schema/interests';
 import { berths } from '@/lib/db/schema/berths';
 import { tags } from '@/lib/db/schema/system';
 import { createAuditLog, type AuditMeta } from '@/lib/audit';
@@ -103,6 +103,10 @@ export async function listClients(portId: string, query: ListClientsInput) {
         .from(companyMemberships)
         .where(and(inArray(companyMemberships.clientId, ids), isNull(companyMemberships.endDate)))
         .groupBy(companyMemberships.clientId),
+      // Latest interest per client + its primary-berth mooring (resolved via
+      // interest_berths join, plan §3.4). The is_primary filter narrows the
+      // join to ≤1 berth row per interest; non-primary links never surface
+      // through this list-page derivation.
       db
         .select({
           clientId: interests.clientId,
@@ -111,7 +115,11 @@ export async function listClients(portId: string, query: ListClientsInput) {
           mooringNumber: berths.mooringNumber,
         })
         .from(interests)
-        .leftJoin(berths, eq(berths.id, interests.berthId))
+        .leftJoin(
+          interestBerths,
+          and(eq(interestBerths.interestId, interests.id), eq(interestBerths.isPrimary, true)),
+        )
+        .leftJoin(berths, eq(berths.id, interestBerths.berthId))
         .where(
           and(
             eq(interests.portId, portId),