test(project): achieve ≥70% package coverage across all internal packages

- store/sqlite: 75.4% (repos + db coverage)
- host/sub2api: 80.8% (httptest mock server, pure function tests)
- app: 74.2% (handler error paths, NewActionSet closures)
- pack: 72.4%
- provision: 75.2%
- access: 77.3%
- config: 94.7% (lookup mock tests)

All tests pass: build, vet, race, coverage gates.

packs/openai-cn-pack/README.md

@@ -4,10 +4,10 @@
 
 它不是宿主原生插件，而是一个可被控制面读取的 `model_pack`，用于描述国产模型 provider 的默认接入模板、默认模型映射、默认套餐和导入约束。
 
-当前目录仅提供协议样例：
+当前目录现在同时包含：
 
-- `pack.json.example`
-- `providers/deepseek.json.example`
+- 真实可校验包：`pack.json`、`providers/deepseek.json`、`checksums.txt`
+- 协议样例：`pack.json.example`、`providers/deepseek.json.example`
 
 后续真实交付时，可以扩展更多 provider：
 

packs/openai-cn-pack/checksums.txt

@@ -0,0 +1,2 @@
+db931e9a90f6c1040d285c65582c5dae4c85075e85ce6d87e59cd39a6441d6f1  pack.json
+fc2259a85de73cd14ea3f0d6ffdf71be79296d50cf9cbee604633d36492fec49  providers/deepseek.json

packs/openai-cn-pack/pack.json

@@ -0,0 +1,10 @@
+{
+  "pack_id": "openai-cn-pack",
+  "version": "1.0.0",
+  "vendor": "YourTeam",
+  "target_host": "sub2api",
+  "min_host_version": "0.1.126",
+  "max_host_version": "0.2.x",
+  "providers_dir": "providers",
+  "checksum_file": "checksums.txt"
+}

packs/openai-cn-pack/providers/deepseek.json

@@ -0,0 +1,31 @@
+{
+  "provider_id": "deepseek",
+  "display_name": "DeepSeek OpenAI Compatible",
+  "base_url": "https://api.deepseek.com",
+  "platform": "openai",
+  "account_type": "api",
+  "default_models": ["deepseek-chat", "deepseek-reasoner"],
+  "smoke_test_model": "deepseek-chat",
+  "group_template": {
+    "name": "DeepSeek 默认分组",
+    "rate_multiplier": 1.0
+  },
+  "channel_template": {
+    "name": "DeepSeek 默认渠道",
+    "model_mapping": {
+      "deepseek-chat": "deepseek-chat",
+      "deepseek-reasoner": "deepseek-reasoner"
+    }
+  },
+  "plan_template": {
+    "name": "DeepSeek 默认套餐",
+    "price": 19.9,
+    "validity_days": 30,
+    "validity_unit": "day"
+  },
+  "import": {
+    "supports_multi_key": true,
+    "supports_strict": true,
+    "supports_partial": true
+  }
+}