fix(audit-2): integration regressions + data-integrity from second-pass review

Two reviewer agents did a second-pass deep audit of the 21-commit
refactor. Eight findings; four fixed here (one was deferred with a
schema comment, three were 🟡 nice-to-haves left for follow-up).

Integration regressions (🟠 high):
- Outbound webhook `interest.berth_linked` now fires from the new
  junction-add handler. Was emitting a socket-only event, leaving
  external integrations silent post-refactor.
- Two new webhook events `interest.berth_unlinked` and
  `interest.berth_link_updated` added to WEBHOOK_EVENTS +
  INTERNAL_TO_WEBHOOK_MAP. PATCH and DELETE handlers now dispatch them
  alongside the existing socket emits — lifecycle parity restored.
- BerthInterestPulse adds useRealtimeInvalidation for berth-link
  events. The query key was berth-scoped while the linked-berths
  dialog invalidates interest-scoped keys (no prefix match), so the
  pulse went stale. Bridges via the realtime hook now.

Recommender semantic fix (🟠 medium-high):
- aggregates CTE: active_interest_count now filters on
  `ib.is_specific_interest = true`, matching the public-map "Under
  Offer" derivation. EOI-bundle-only links no longer demote a berth
  to Tier C for other reps. Smoke test confirms previously-all-Tier-C
  results now correctly classify as Tier A.
- Same CTE: `total_interest_count` uses COUNT(ib.berth_id) instead of
  COUNT(*) so a berth with no junction rows reports 0 (not 1 from
  the LEFT JOIN's NULL-right-side row). Prevents heat over-counting.

Data integrity (🟠):
- AcroForm tier rejects negative numerics in coerceFieldValue (was
  letting through `length_ft="-50"` which would poison the
  recommender feasibility filter on apply).
- FilesystemBackend.resolveHmacSecret throws in production when
  storage_proxy_hmac_secret_encrypted is null. Dev still derives from
  BETTER_AUTH_SECRET for ergonomics; prod must explicitly configure.
- Documented the circular FK between berths.current_pdf_version_id
  and berth_pdf_versions.id. Drizzle's `.references()` can't express
  the cycle so the schema column is plain text + a comment; the FK
  is authoritatively maintained by migration 0030.

Tests still 1163/1163. tsc clean.

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

src/app/api/v1/interests/[id]/berths/handlers.ts

@@ -92,6 +92,15 @@ export const addHandler: RouteHandler = async (req, ctx, params) => {
       interestId,
       berthId: body.berthId,
     });
+    // Outbound webhook: the legacy /link-berth path dispatched
+    // `interest.berth_linked` and external integrations subscribe to it.
+    // The new junction-add path must keep that contract.
+    void import('@/lib/services/webhook-dispatch').then(({ dispatchWebhookEvent }) =>
+      dispatchWebhookEvent(ctx.portId, 'interest:berthLinked', {
+        interestId,
+        berthId: body.berthId,
+      }),
+    );
 
     return NextResponse.json({ data: link }, { status: 201 });
   } catch (error) {