fix(safety): plug 3 EMAIL_REDIRECT_TO leaks + 10 unit tests + live smoke

A pre-import audit caught three places where outbound comms could escape
even with EMAIL_REDIRECT_TO set. Plugged each, added unit tests so the
behavior can't silently regress, and shipped a live smoke script the
operator can run before any production data import.

Leak 1: email-compose.service.ts (per-account user composer)
  Built its own nodemailer transporter and called sendMail() directly,
  bypassing the centralized sendEmail()'s redirect. Now mirrors the same
  redirect: when EMAIL_REDIRECT_TO is set, "to" is rewritten, "cc" is
  dropped, and the subject is prefixed with "[redirected from <orig>]".

Leak 2: documenso-client.sendDocument()
  Tells Documenso to actually email the document. Recipient emails were
  rerouted at create-time (in pass-3) but a document created BEFORE the
  redirect was turned on could still trigger a real-client email. Now
  short-circuited when the redirect is set — returns the existing doc
  shape so downstream code doesn't see an unexpected null.

Leak 3: documenso-client.sendReminder()
  Same shape as sendDocument: emails a stored recipient address that may
  predate the redirect. Now short-circuits with a warn-level log.

Tests (tests/unit/comms-safety.test.ts):
  - createDocument rewrites recipients
  - generateDocumentFromTemplate rewrites both v1.13 formValues.*Email
    keys AND v2.x recipients[] arrays
  - sendDocument is short-circuited (no /send call)
  - sendReminder is short-circuited (no /remind call)
  - createDocument passes through unchanged when redirect unset
  - sendEmail rewrites to + subject for single recipient
  - sendEmail handles array of recipients (joined into subject prefix)
  - sendEmail passes through unchanged when redirect unset
  - Webhook worker reads process.env.EMAIL_REDIRECT_TO at dispatch time
    (no module-level caching that could miss a runtime flip)

Live smoke (scripts/smoke-test-redirect.ts):
  Monkey-patches nodemailer.createTransport, calls the real sendEmail()
  with a fake real-client address, verifies the captured outbound has
  the right "to" + subject. Run: `pnpm tsx scripts/smoke-test-redirect.ts`.
  Exits non-zero if the redirect failed for any reason — drop-in for a
  pre-deploy check.

Verification:
  pnpm exec tsc --noEmit       — 0 errors
  pnpm exec vitest run         — 936/936 (was 926, +10 new safety tests)
  pnpm tsx scripts/smoke-test-redirect.ts — PASS

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

src/lib/services/documenso-client.ts

@@ -180,7 +180,26 @@ export async function generateDocumentFromTemplate(
   ).then(normalizeDocument);
 }
 
+/**
+ * Tell Documenso to actually email the document to its recipients. The
+ * recipients themselves are set at create-time (and rerouted to
+ * EMAIL_REDIRECT_TO when set), but this is a belt-and-braces guard for
+ * documents that may have been created BEFORE the redirect was turned on
+ * (i.e. real-recipient documents now triggered by an automation while
+ * we're trying to hold comms). When the redirect is on we skip the API
+ * call entirely and return a synthetic "still pending" response.
+ */
 export async function sendDocument(docId: string, portId?: string): Promise<DocumensoDocument> {
+  if (env.EMAIL_REDIRECT_TO) {
+    logger.warn(
+      { docId, portId, redirect: env.EMAIL_REDIRECT_TO },
+      'sendDocument SKIPPED — EMAIL_REDIRECT_TO is set, outbound comms paused',
+    );
+    // Return the existing doc shape so downstream code doesn't see an
+    // unexpected null. The document remains in DRAFT/PENDING from
+    // Documenso's perspective.
+    return getDocument(docId, portId);
+  }
   return documensoFetch(
     `/api/v1/documents/${docId}/send`,
     {
@@ -194,11 +213,23 @@ export async function getDocument(docId: string, portId?: string): Promise<Docum
   return documensoFetch(`/api/v1/documents/${docId}`, undefined, portId).then(normalizeDocument);
 }
 
+/**
+ * Email a signing reminder to one recipient. Skipped entirely when
+ * EMAIL_REDIRECT_TO is set — the recipient's stored email may still be
+ * a real client address from before the redirect was enabled.
+ */
 export async function sendReminder(
   docId: string,
   signerId: string,
   portId?: string,
 ): Promise<void> {
+  if (env.EMAIL_REDIRECT_TO) {
+    logger.warn(
+      { docId, signerId, portId, redirect: env.EMAIL_REDIRECT_TO },
+      'sendReminder SKIPPED — EMAIL_REDIRECT_TO is set, outbound comms paused',
+    );
+    return;
+  }
   await documensoFetch(
     `/api/v1/documents/${docId}/recipients/${signerId}/remind`,
     {