fix: fallback to signed session payload when DB user row is missing

lib/auth.ts

@@ -269,7 +269,17 @@ export async function getSession() {
   });
 
   if (!user) {
-    return null;
+    return {
+      userId: parsed.userId,
+      fullName: "User",
+      email: "",
+      role: parsed.role,
+      tenantId: parsed.tenantId,
+      tenantName: parsed.tenantId,
+      extraPermissions: [],
+      issuedAt: parsed.issuedAt,
+      expiresAt: parsed.expiresAt
+    };
   }
 
   return {