Merge SERVICE role into AGENT

Every AGENT now gets an auto-generated API key on creation, shown once
in a modal. AGENTs log in with password and authenticate to the API
with X-Api-Key. pre-push.sql defensively migrates any residual SERVICE
rows to AGENT before Prisma rewrites the enum. Goddard is no longer
baked into the seed — create agents via Admin → Users.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

server/prisma/pre-push.sql

@@ -0,0 +1,14 @@
+-- Idempotent SQL applied BEFORE `prisma db push`.
+-- Flips any residual SERVICE-role users to AGENT before Prisma rewrites the Role enum.
+-- Safe no-op on fresh databases or databases already migrated past the SERVICE role.
+
+DO $$
+BEGIN
+  IF EXISTS (
+    SELECT 1 FROM pg_type t
+    JOIN pg_enum e ON e.enumtypid = t.oid
+    WHERE t.typname = 'Role' AND e.enumlabel = 'SERVICE'
+  ) THEN
+    EXECUTE 'UPDATE "User" SET "role" = ''AGENT'' WHERE "role"::text = ''SERVICE''';
+  END IF;
+END $$;