feat(uat-batch-6): external-EOI structured signatories + X/Y signed counter

Replace the freetext CSV signer-names field with a structured recipient
editor (name / email / role per row). Service now persists each
non-CC signatory as a `document_signers` row pre-stamped
`status='signed'` so the document-detail "X / Y signed" badge counts
correctly for manually-uploaded EOIs.

- ExternalEoiInput gains a structured `signatories` field; legacy
  `signerNames` retained for back-compat. Role enum:
  `client | developer | rep | witness | cc`.
- uploadExternallySignedEoi inserts `document_signers` rows for every
  non-CC entry inside the existing transaction.
- documentEvents.completed event records both shapes for full audit
  fidelity.
- POST /api/v1/interests/[id]/external-eoi parses the `signatories`
  JSON multipart field defensively; malformed payloads fall back to
  signerNames.
- Dialog UI: per-row Name / Email / Role inputs with add / remove.
  Seeds from interest's clientName + clientPrimaryEmail via a
  signatoriesOverride/null pattern (React-Compiler safe — no
  setState-in-effect).

tsc clean. 1419/1419 vitest pass.

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

src/lib/services/external-eoi.service.ts

@@ -12,7 +12,7 @@ import { eq } from 'drizzle-orm';
 
 import { db } from '@/lib/db';
 import { interests } from '@/lib/db/schema/interests';
-import { documents, documentEvents, files } from '@/lib/db/schema/documents';
+import { documents, documentEvents, documentSigners, files } from '@/lib/db/schema/documents';
 import { ports } from '@/lib/db/schema/ports';
 import { env } from '@/lib/env';
 import { buildStoragePath } from '@/lib/minio';
@@ -21,6 +21,15 @@ import { createAuditLog, type AuditMeta } from '@/lib/audit';
 import { CodedError, NotFoundError, ValidationError } from '@/lib/errors';
 import { emitToRoom } from '@/lib/socket/server';
 
+/** A single signatory on an externally-signed document. */
+export interface ExternalSignatory {
+  name: string;
+  email: string;
+  /** Drives auto-fill on the dialog + downstream "Email copy" recipient
+   *  list. `cc` recipients aren't signers but show up on send-out lists. */
+  role: 'client' | 'developer' | 'rep' | 'witness' | 'cc';
+}
+
 export interface ExternalEoiInput {
   interestId: string;
   portId: string;
@@ -30,8 +39,14 @@ export interface ExternalEoiInput {
   title?: string;
   /** When the signing actually happened (the date on the paper / contract). */
   signedAt?: Date;
-  /** Names of the people who signed (free-text — we don't manage signer
-   *  identities for external sigs). Recorded in metadata. */
+  /**
+   * Structured signatory list — preferred over the legacy `signerNames`
+   * CSV. When present, the service inserts one `document_signers` row
+   * per non-CC entry pre-stamped `status='signed'` so the
+   * "X / Y signed" badge renders correctly downstream.
+   */
+  signatories?: ExternalSignatory[];
+  /** Legacy CSV form kept for backwards compat with older callers. */
   signerNames?: string[];
   /** Free-text note (e.g. "signed in person at boat show"). */
   notes?: string;
@@ -123,14 +138,35 @@ export async function uploadExternallySignedEoi(input: ExternalEoiInput) {
       });
     }
 
+    // Backfill document_signers rows for the structured signatory list
+    // so the document-detail "X / Y signed" badge counts correctly. CC
+    // recipients aren't signatories — they're recipients of the email
+    // copy and don't show up in the signed-count denominator.
+    const signedAtMoment = input.signedAt ?? new Date();
+    const signerRows = (input.signatories ?? [])
+      .filter((s) => s.role !== 'cc')
+      .map((s, i) => ({
+        documentId: doc.id,
+        signerName: s.name,
+        signerEmail: s.email,
+        signerRole: s.role,
+        signingOrder: i + 1,
+        status: 'signed' as const,
+        signedAt: signedAtMoment,
+      }));
+    if (signerRows.length > 0) {
+      await tx.insert(documentSigners).values(signerRows);
+    }
+
     await tx.insert(documentEvents).values({
       documentId: doc.id,
       eventType: 'completed',
       eventData: {
         isManualUpload: true,
         external: true,
-        signerNames: input.signerNames ?? [],
-        signedAt: (input.signedAt ?? new Date()).toISOString(),
+        signerNames: input.signerNames ?? (input.signatories ?? []).map((s) => s.name),
+        signatories: input.signatories ?? null,
+        signedAt: signedAtMoment.toISOString(),
         fileId: fileRecord.id,
       },
     });