feat(eoi): dual-path generateAndSign (inapp + documenso-template)

generateAndSign now accepts a `pathway` parameter:

- `inapp` (existing): resolve in-app template -> pdfme -> MinIO -> Documenso
  createDocument + sendDocument.
- `documenso-template` (new): build EOI context from interestId, assemble
  the Documenso template payload, and call Documenso's
  /api/v1/templates/{id}/generate-document. Documenso owns the PDF; we
  still record a documents row for tracking.

Adds generateDocumentFromTemplate helper to the Documenso client and new
env vars (DOCUMENSO_TEMPLATE_ID_EOI + client/developer/approval recipient
IDs) with defaults matching the legacy flow. Covered by 6 new integration
tests (637/637 green).

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

src/lib/validators/document-templates.ts

@@ -38,6 +38,7 @@ export const generateAndSendSchema = generateSchema.extend({
 });
 
 export const generateAndSignSchema = generateSchema.extend({
+  pathway: z.enum(['inapp', 'documenso-template']).default('inapp'),
   signers: z
     .array(
       z.object({
@@ -47,7 +48,8 @@ export const generateAndSignSchema = generateSchema.extend({
         signingOrder: z.number().int().min(1),
       }),
     )
-    .min(1),
+    .optional()
+    .default([]),
 });
 
 export type CreateTemplateInput = z.infer<typeof createTemplateSchema>;