chore(migrations): 合并 ephemeral cache 迁移到 20260423000000，移除冗余迁移文件并同步 baseline cutoff

crates/aether-data/migrations/20260423000000_fix_provider_api_key_api_formats_nullable.sql

@@ -32,3 +32,7 @@ WHERE p.id = pak.provider_id
       )
     )
   );
+
+ALTER TABLE public.stats_daily_model
+    ADD COLUMN IF NOT EXISTS cache_creation_ephemeral_5m_tokens bigint DEFAULT '0'::bigint NOT NULL,
+    ADD COLUMN IF NOT EXISTS cache_creation_ephemeral_1h_tokens bigint DEFAULT '0'::bigint NOT NULL;

crates/aether-data/migrations/20260423010000_add_ephemeral_cache_to_stats_daily_model.sql

@@ -1,3 +0,0 @@
-ALTER TABLE public.stats_daily_model
-    ADD COLUMN IF NOT EXISTS cache_creation_ephemeral_5m_tokens bigint DEFAULT '0'::bigint NOT NULL,
-    ADD COLUMN IF NOT EXISTS cache_creation_ephemeral_1h_tokens bigint DEFAULT '0'::bigint NOT NULL;