feat(documenso-phase-6): activity badges + per-document invitation message

Two of the six Phase 6 polish items shipped in one commit because they
share the data + plumbing path (per-doc message uses the signing-
progress UI's existing layout).

1) Signing-progress activity badges
   - Surfaces `invitedAt`, `openedAt`, `lastReminderSentAt` (all
     populated by Phase 1+2 webhook handlers) per signer in the
     existing progress widget. Each badge renders as
     "Invited 2 hours ago / Opened yesterday / Reminded 3 days ago"
     via Intl.RelativeTimeFormat.
   - Resend button: was silent on success/failure; now uses
     useMutation + toast so the rep sees whether the reminder fired
     or fell into a cadence cooldown. Honours the existing
     sendReminderIfAllowed return shape (`{sent, reason}`).
   - Title-tooltips on each badge show the exact ISO timestamp.

2) Per-document custom invitation message
   - New `documents.invitation_message` column (migration 0060;
     applied via psql per the dev-flow note in CLAUDE.md).
   - Textarea in UploadForSigningDialog step 2 (recipient configurator),
     1000-char cap, placeholder text shows the expected tone.
   - custom-document-upload.service accepts `invitationMessage`,
     trims + stores on the documents row.
   - sendCascadingInviteForNextSigner now reads
     doc.invitationMessage and passes as customMessage so every
     cascaded recipient (developer / approver / witness) sees the
     same note — not just the first signer.
   - send-invitation route (manual resend path) reads the same
     column → customMessage so manual reminders match.
   - The email template's existing customMessage rendering does
     the XSS escape; no other plumbing needed.

Phase 6 items still deferred (each ~2-3h, mostly independent):
- Auto-send delay (`eoi_send_delay_minutes` setting + scheduled
  BullMQ job — needs a scheduler hook).
- Document expiration (`documents.expires_at` + Documenso
  `expiresAt` passthrough — needs Documenso v2 endpoint shape
  verification).
- Failed-webhook recovery admin UI (the BullMQ DLQ exists; needs
  an admin page with Replay button).

Tests: 1340 → 1350 ✅; tsc clean.

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

src/lib/db/migrations/0060_documents_invitation_message.sql

@@ -0,0 +1,8 @@
+-- Phase 6 polish: per-document custom invitation message
+--
+-- Rep can author a short note in the upload-for-signing dialog that
+-- gets inserted above the CTA in every signing-invitation email for
+-- this document. Plain text (XSS-escaped by the email renderer).
+-- Null means "no custom message — use the template default".
+ALTER TABLE documents
+  ADD COLUMN IF NOT EXISTS invitation_message text;

src/lib/db/schema/documents.ts

@@ -94,6 +94,11 @@ export const documents = pgTable(
      *  N days until they complete. Null = manual reminders only. */
     autoReminderIntervalDays: integer('auto_reminder_interval_days'),
     notes: text('notes'),
+    /** Phase 6 polish — rep-authored note inserted above the CTA in
+     *  every signing-invitation email for THIS document. Falls back to
+     *  the empty string when null. Plain-text (XSS-escaped by the
+     *  email renderer); not Markdown. */
+    invitationMessage: text('invitation_message'),
     remindersDisabled: boolean('reminders_disabled').notNull().default(false),
     reminderCadenceOverride: integer('reminder_cadence_override'),
     createdBy: text('created_by').notNull(),

src/lib/services/custom-document-upload.service.ts

@@ -93,6 +93,11 @@ export interface UploadDocumentForSigningArgs {
    *  it to the resolved Documenso recipient id after createDocument
    *  responds. */
   fields: Array<Omit<DocumensoFieldPlacement, 'recipientId'> & { recipientIndex: number }>;
+  /** Phase 6 polish — optional rep-authored note inserted above the
+   *  CTA in every signing-invitation email for this document. Stored
+   *  on documents.invitation_message; falls back to the template
+   *  default when null/empty. */
+  invitationMessage?: string | null;
   meta: AuditMeta;
 }
 
@@ -121,6 +126,7 @@ export async function uploadDocumentForSigning(
     filename,
     recipients,
     fields,
+    invitationMessage,
     meta,
   } = args;
 
@@ -239,6 +245,7 @@ export async function uploadDocumentForSigning(
       documentType,
       title,
       status: 'draft',
+      invitationMessage: invitationMessage?.trim() || null,
       createdBy: meta.userId,
     })
     .returning();
@@ -390,6 +397,7 @@ export async function uploadDocumentForSigning(
           documentLabel: DOC_TYPE_LABEL[documentType] ?? 'Sales Contract',
           signerRole: (refreshed.signerRole as SignerRole) ?? 'client',
           senderName: docCfg.developerName ?? null,
+          customMessage: invitationMessage?.trim() || null,
         }).catch((err) => {
           logger.error(
             { err, documentId: docRow.id, signerId: refreshed.id },

src/lib/services/documents.service.ts

@@ -1105,12 +1105,17 @@ export async function handleRecipientSigned(eventData: {
  * can be exercised by a dedicated unit test. Finds the next pending
  * signer (lowest signing order), sends them a branded invitation, and
  * stamps `invitedAt` so a duplicate webhook delivery doesn't re-send.
+ *
+ * Phase 6: when the document carries a rep-authored
+ * `invitation_message`, it flows through as `customMessage` so every
+ * cascaded recipient (not just the first one) sees the same note.
  */
 async function sendCascadingInviteForNextSigner(doc: {
   id: string;
   portId: string;
   documentType: string;
   title: string;
+  invitationMessage: string | null;
 }): Promise<void> {
   const signers = await db
     .select()
@@ -1145,6 +1150,7 @@ async function sendCascadingInviteForNextSigner(doc: {
     documentLabel: DOC_TYPE_LABEL[doc.documentType] ?? 'Expression of Interest',
     signerRole: (next.signerRole as SignerRole) ?? 'other',
     senderName: docCfg.developerName ?? null,
+    customMessage: doc.invitationMessage,
   });
 
   await db