feat(interests): upload externally-signed EOI (paper / non-Documenso)

Sales reps need to file EOIs that were signed outside Documenso —
on paper, in person at a boat show, or via an alternate e-sign vendor.
Until now the EOI flow assumed Documenso was the only path.

- external-eoi.service.uploadExternallySignedEoi creates BOTH the
  document row AND the signed-file record in one shot. Document is
  marked isManualUpload=true with status=completed and signedFileId
  set. Distinct from the existing uploadSignedManually which augments
  a document row that came from the Documenso pathway.
- POST /api/v1/interests/[id]/external-eoi accepts multipart with the
  PDF + optional title + signedAt date + comma-separated signer names
  + free-text notes. Gated on documents.upload_signed permission.
- Interest stage auto-advances to eoi_signed (only when the interest
  is currently at or before eoi_sent — past that, just file the doc).
- The signing date, signer names, and any notes are captured into
  document_events.eventData + the audit_log metadata so the audit
  trail records who said the document was signed and when.
- ExternalEoiUploadDialog renders a small modal: file picker, title
  override, signed-date (defaults to today), comma-separated signer
  names, notes. Wired into interest-detail-header behind an Upload
  icon button (gated on documents.upload_signed).

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

src/components/interests/interest-detail-header.tsx

@@ -13,6 +13,7 @@ import {
   MessageCircle,
   Phone,
   AlarmClock,
+  Upload,
 } from 'lucide-react';
 import Link from 'next/link';
 
@@ -23,6 +24,7 @@ import { ArchiveConfirmDialog } from '@/components/shared/archive-confirm-dialog
 import { DetailHeaderStrip } from '@/components/shared/detail-header-strip';
 import { PermissionGate } from '@/components/shared/permission-gate';
 import { InterestForm } from '@/components/interests/interest-form';
+import { ExternalEoiUploadDialog } from '@/components/interests/external-eoi-upload-dialog';
 import { InlineStagePicker } from '@/components/interests/inline-stage-picker';
 import { InterestOutcomeDialog } from '@/components/interests/interest-outcome-dialog';
 import { apiFetch } from '@/lib/api/client';
@@ -102,6 +104,7 @@ export function InterestDetailHeader({ portSlug, interest }: InterestDetailHeade
   const [editOpen, setEditOpen] = useState(false);
   const [archiveOpen, setArchiveOpen] = useState(false);
   const [outcomeDialog, setOutcomeDialog] = useState<null | 'won' | 'lost'>(null);
+  const [externalEoiOpen, setExternalEoiOpen] = useState(false);
 
   const isArchived = !!interest.archivedAt;
   const outcomeBadge = resolveOutcomeBadge(interest.outcome);
@@ -376,6 +379,20 @@ export function InterestDetailHeader({ portSlug, interest }: InterestDetailHeade
                 </>
               )}
             </PermissionGate>
+            <PermissionGate resource="documents" action="upload_signed">
+              <button
+                type="button"
+                onClick={() => setExternalEoiOpen(true)}
+                aria-label="Upload externally-signed EOI"
+                title="Upload externally-signed EOI (paper / outside Documenso)"
+                className={cn(
+                  'rounded-md p-1.5 text-muted-foreground/70 transition-colors',
+                  'hover:bg-foreground/5 hover:text-foreground',
+                )}
+              >
+                <Upload className="size-4" />
+              </button>
+            </PermissionGate>
             <PermissionGate resource="interests" action="edit">
               <button
                 type="button"
@@ -439,6 +456,12 @@ export function InterestDetailHeader({ portSlug, interest }: InterestDetailHeade
         }}
         isLoading={archiveMutation.isPending || restoreMutation.isPending}
       />
+
+      <ExternalEoiUploadDialog
+        open={externalEoiOpen}
+        onOpenChange={setExternalEoiOpen}
+        interestId={interest.id}
+      />
     </>
   );
 }