refactor(services): centralize AuditMeta + transactional setEntityTags helper

The same `interface AuditMeta { userId; portId; ipAddress; userAgent }`
was duplicated in 26 service files. Move the canonical definition into
`@/lib/audit` next to the related types and update every service to
import it. `ServiceAuditMeta` (the alias used in invoices.ts and
expenses.ts) collapses into the same name.

Tag CRUD across clients/companies/yachts/interests/berths followed an
identical wipe-then-rewrite recipe with two latent issues: the delete
and insert weren't wrapped in a transaction (a partial failure left
the entity with zero tags) and the audit-log payload shape diverged
(`newValue: { tagIds }` for clients/yachts/companies but
`metadata: { type: 'tags_updated', tagIds }` for interests/berths).

Extract `setEntityTags` in `entity-tags.helper.ts` that performs the
delete+insert inside a single transaction, normalizes the audit payload
to `newValue: { tagIds }`, and dispatches the per-entity socket event
through a switch so `ServerToClientEvents` typing stays intact.

The five `setXTags(...)` service functions now do parent-row tenant
verification and delegate the join-table work + side effects.

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

src/lib/services/interests.service.ts

@@ -7,9 +7,10 @@ import { berths } from '@/lib/db/schema/berths';
 import { yachts } from '@/lib/db/schema/yachts';
 import { companyMemberships } from '@/lib/db/schema/companies';
 import { tags } from '@/lib/db/schema/system';
-import { createAuditLog } from '@/lib/audit';
+import { createAuditLog, type AuditMeta } from '@/lib/audit';
 import { NotFoundError, ConflictError, ValidationError } from '@/lib/errors';
 import { emitToRoom } from '@/lib/socket/server';
+import { setEntityTags } from '@/lib/services/entity-tags.helper';
 import { buildListQuery } from '@/lib/db/query-builder';
 import { diffEntity } from '@/lib/entity-diff';
 import { softDelete, restore, withTransaction } from '@/lib/db/utils';
@@ -22,13 +23,6 @@ import type {
 
 // ─── Types ────────────────────────────────────────────────────────────────────
 
-interface AuditMeta {
-  userId: string;
-  portId: string;
-  ipAddress: string;
-  userAgent: string;
-}
-
 // ─── Yacht ownership validator ───────────────────────────────────────────────
 
 async function assertYachtBelongsToClient(
@@ -552,26 +546,18 @@ export async function setInterestTags(
     throw new NotFoundError('Interest');
   }
 
-  await db.delete(interestTags).where(eq(interestTags.interestId, id));
-
-  if (tagIds.length > 0) {
-    await db.insert(interestTags).values(tagIds.map((tagId) => ({ interestId: id, tagId })));
-  }
-
-  void createAuditLog({
-    userId: meta.userId,
-    portId,
-    action: 'update',
-    entityType: 'interest',
+  const result = await setEntityTags({
+    joinTable: interestTags,
+    entityColumn: interestTags.interestId,
+    tagColumn: interestTags.tagId,
     entityId: id,
-    metadata: { type: 'tags_updated', tagIds },
-    ipAddress: meta.ipAddress,
-    userAgent: meta.userAgent,
+    portId,
+    tagIds,
+    meta,
+    entityType: 'interest',
   });
 
-  emitToRoom(`port:${portId}`, 'interest:updated', { interestId: id, changedFields: ['tags'] });
-
-  return { interestId: id, tagIds };
+  return { interestId: result.entityId, tagIds: result.tagIds };
 }
 
 // ─── Link / Unlink Berth ──────────────────────────────────────────────────────