refactor: 移除 LiteLLM proxy 架构，后端直连 Provider API

- 移除 backend/scripts/build_litellm_proxy_config.py
- 简化 LiteLLMService，移除 run_completion_with_cost 方法
- AgentScopeRunner 改为从 LlmFactory 获取 api_base 和 api_key
- 部署配置移除 litellm/litellm-config-job 服务
- Flutter 新增 AuthBootScreen 引导页
- Android 添加通知权限 (POST_NOTIFICATIONS, RECEIVE_BOOT_COMPLETED, SCHEDULE_EXACT_ALARM)
- 优化 LocalNotificationService 调度失败 fallback
- 更新 manifest.json (version 3)

backend/tests/unit/services/test_litellm_service.py

@@ -31,37 +31,6 @@ def test_calculate_cost_uses_second_qwen_tier() -> None:
     assert cost == pytest.approx(0.1856)
 
 
-def test_run_completion_extracts_usage_and_cost() -> None:
-    service = LiteLLMService()
-    captured: dict[str, object] = {}
-
-    def _fake_completion(**kwargs: object) -> dict[str, object]:
-        captured.update(kwargs)
-        return {
-            "model": "dashscope/qwen3.5-flash",
-            "usage": {
-                "prompt_tokens": 2000,
-                "completion_tokens": 100,
-                "total_tokens": 2100,
-                "prompt_tokens_details": {"cached_tokens": 500},
-            },
-            "choices": [{"message": {"content": "ok"}}],
-        }
-
-    result = service.run_completion_with_cost(
-        model="dashscope/qwen3.5-flash",
-        messages=[{"role": "user", "content": "hello"}],
-        response_format={"type": "json_object"},
-        completion_fn=_fake_completion,
-    )
-
-    assert result.usage.prompt_tokens == 2000
-    assert result.usage.completion_tokens == 100
-    assert result.usage.total_tokens == 2100
-    assert result.usage.cost == pytest.approx(0.00051)
-    assert captured["response_format"] == {"type": "json_object"}
-
-
 def test_build_usage_metadata_calculates_cost_from_usage_summary() -> None:
     service = LiteLLMService()