refactor(db): move rate-limit extras into Prisma migration and remove db-extras script

prisma/migrations/20260226110000_rate_limit_extras/migration.sql

@@ -0,0 +1,44 @@
+-- Rate limiting extras migration
+-- Keeps compatibility with existing environments created via prisma db push.
+
+CREATE TABLE IF NOT EXISTS rate_limits (
+    id SERIAL PRIMARY KEY,
+    key VARCHAR(255) NOT NULL,
+    action VARCHAR(50) NOT NULL,
+    count INTEGER NOT NULL DEFAULT 1,
+    window_start TIMESTAMP NOT NULL DEFAULT NOW()
+);
+
+DO $$
+BEGIN
+    IF NOT EXISTS (
+        SELECT 1
+        FROM pg_constraint
+        WHERE conname = 'rate_limits_key_action_key'
+    ) THEN
+        ALTER TABLE rate_limits
+            ADD CONSTRAINT rate_limits_key_action_key UNIQUE (key, action);
+    END IF;
+END $$;
+
+CREATE INDEX IF NOT EXISTS idx_rate_limits_key_action ON rate_limits(key, action);
+CREATE INDEX IF NOT EXISTS idx_rate_limits_window_start ON rate_limits(window_start);
+
+DO $$
+BEGIN
+    IF EXISTS (
+        SELECT 1
+        FROM pg_class
+        WHERE relname = 'rate_limits'
+          AND relkind = 'r'
+          AND relpersistence <> 'u'
+    ) THEN
+        ALTER TABLE rate_limits SET UNLOGGED;
+    END IF;
+END $$;
+
+CREATE OR REPLACE FUNCTION cleanup_rate_limits() RETURNS void AS $$
+BEGIN
+    DELETE FROM rate_limits WHERE window_start < NOW() - INTERVAL '1 hour';
+END;
+$$ LANGUAGE plpgsql;