feat(06-01): install packages + extend schema + generate migration

- installed signature_pad, @react-email/render, @react-email/components
- added signingTokens table (jti pk, documentId, expiresAt, usedAt)
- added auditEvents table with auditEventTypeEnum (6 event types)
- added signedFilePath, pdfHash, signedAt columns to documents table
- generated and applied migration 0005_signing_flow.sql

teressa-copeland-homes/drizzle/meta/_journal.json

@@ -36,6 +36,13 @@
       "when": 1773987640772,
       "tag": "0004_military_maximus",
       "breakpoints": true
+    },
+    {
+      "idx": 5,
+      "version": "7",
+      "when": 1774027394708,
+      "tag": "0005_signing_flow",
+      "breakpoints": true
     }
   ]
 }