feat: provider api_formats 可空继承、OpenAI 图片 edit/variation 与用量配额多项补强

- 鉴权: provider_api_keys.api_formats 改为可空，OAuth 托管 key 自动继承 provider endpoints 激活格式，相关 handler/测试同步更新
- 图片 planner: OpenAI 图片路由新增 edit/variation 操作并完善参数校验、响应合并与流式处理
- 用量: user me usage 返回区分 client_requested_stream/upstream_is_stream，前端 usage 列表筛选与展示增强
- 统计: stats_daily_model 新增 cache_creation_ephemeral_5m/1h tokens 字段与回填链路
- 配额/observability: quota repository 新增内存与 SQL 扩展，admin observability usage 字段扩充
- 其它: OAuth 导入/轮询收敛、provider 汇总与 pool admin 读写链路小修、新增 system_config 缓存与 provider template handler

Closes #318

Co-authored-by: Entropy.Xu <53283266+Entropy-Xu@users.noreply.github.com>

crates/aether-data/migrations/20260403000000_baseline.sql

@@ -494,7 +494,7 @@ CREATE TABLE IF NOT EXISTS public.provider_api_keys (
     created_at timestamp with time zone DEFAULT now() NOT NULL,
     updated_at timestamp with time zone DEFAULT now() NOT NULL,
     provider_id character varying(36) NOT NULL,
-    api_formats json DEFAULT '[]'::json NOT NULL,
+    api_formats json,
     rate_multipliers json,
     health_by_format jsonb,
     circuit_breaker_by_format jsonb,

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

@@ -0,0 +1,34 @@
+ALTER TABLE public.provider_api_keys
+    ALTER COLUMN api_formats DROP DEFAULT,
+    ALTER COLUMN api_formats DROP NOT NULL;
+
+UPDATE public.provider_api_keys AS pak
+SET
+    api_formats = NULL,
+    updated_at = NOW()
+FROM public.providers AS p
+WHERE p.id = pak.provider_id
+  AND pak.api_formats IS NOT NULL
+  AND pak.api_formats::jsonb = '[]'::jsonb
+  AND (
+    (
+      LOWER(BTRIM(p.provider_type)) IN (
+        'claude_code',
+        'codex',
+        'gemini_cli',
+        'vertex_ai',
+        'antigravity'
+      )
+      AND LOWER(BTRIM(pak.auth_type)) = 'oauth'
+    )
+    OR (
+      LOWER(BTRIM(p.provider_type)) = 'kiro'
+      AND (
+        LOWER(BTRIM(pak.auth_type)) = 'oauth'
+        OR (
+          LOWER(BTRIM(pak.auth_type)) = 'bearer'
+          AND COALESCE(BTRIM(pak.auth_config), '') <> ''
+        )
+      )
+    )
+  );

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

@@ -0,0 +1,3 @@
+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;