feat: improve agent workbench and digital human flows

migrations/20260624000001_restore_new_user_starter_credit.sql

@@ -0,0 +1,13 @@
+-- Restore the documented $1 starter credit for existing user default keys.
+-- Keep explicit admin/recharge limits intact, and never leave default user keys
+-- with NULL max_cost because NULL is treated as unlimited by the proxy path.
+UPDATE downstream_api_keys
+SET max_cost = 1.0,
+    updated_at = datetime('now')
+WHERE user_id IS NOT NULL
+  AND (max_cost IS NULL OR max_cost <= 0.0)
+  AND (
+      name LIKE '% 的默认密钥'
+      OR name LIKE '% default key'
+      OR key LIKE 'sk-user-%'
+  );

migrations/20260625000001_route_and_event_query_indexes.sql

@@ -0,0 +1,17 @@
+CREATE INDEX IF NOT EXISTS proxy_logs_created_at_desc_idx
+    ON proxy_logs (created_at DESC, id DESC);
+
+CREATE INDEX IF NOT EXISTS route_channels_route_enabled_cooldown_idx
+    ON route_channels (route_id, enabled, cooldown_until, account_id, token_id);
+
+CREATE INDEX IF NOT EXISTS token_routes_enabled_id_idx
+    ON token_routes (enabled, id);
+
+CREATE INDEX IF NOT EXISTS accounts_id_status_site_idx
+    ON accounts (id, status, site_id);
+
+CREATE INDEX IF NOT EXISTS sites_id_status_url_idx
+    ON sites (id, status, url);
+
+CREATE INDEX IF NOT EXISTS account_tokens_id_enabled_idx
+    ON account_tokens (id, enabled);