feat(provider): 增加 Claude Code 适配器、高级配置能力与 OAuth 账号类型统一解析

- 新增 Claude Code provider adapter (context, envelope, plugin, constants)
- 扩展 provider admin 路由，支持 Claude Code 高级配置 (CRUD)
- 统一 OAuth 账号类型解析逻辑，前后端对齐
- 重构 BatchAssignModelsDialog / ModelMappingDialog，简化组件逻辑
- handler 基类增强: request_builder 支持 Claude Code 信封格式
- CLI stream/sync mixin 适配 Claude Code 流式与同步模式
- 扩展 candidate builder / failover / scheduler 对 Claude Code 的支持
- 前端增加请求时间线可视化 (HorizontalRequestTimeline)
- 补充 Claude Code envelope / runtime controls / distributed sessions 等测试

Closes #183
Closes #185

Co-Authored-By: AAEE86 <ppk0227@hotmail.com>

tests/core/api_format/conversion/test_claude_normalizer.py

@@ -283,6 +283,40 @@ def test_claude_stream_chunk_and_event_roundtrip_basic() -> None:
     assert out_events[-1]["type"] == "message_stop"
 
 
+def test_claude_stream_message_start_preserves_usage() -> None:
+    n = ClaudeNormalizer()
+    state = StreamState(model="claude-3-sonnet")
+
+    chunk = {
+        "type": "message_start",
+        "message": {
+            "id": "msg_usage_start",
+            "type": "message",
+            "role": "assistant",
+            "model": "claude-3-sonnet",
+            "content": [],
+            "usage": {
+                "input_tokens": 9,
+                "output_tokens": 0,
+                "cache_read_input_tokens": 3,
+            },
+        },
+    }
+
+    events = n.stream_chunk_to_internal(chunk, state)
+    assert len(events) == 1
+    start_event = events[0]
+    assert isinstance(start_event, MessageStartEvent)
+    assert start_event.usage is not None
+    assert start_event.usage.input_tokens == 9
+    assert start_event.usage.cache_read_tokens == 3
+
+    out = n.stream_event_from_internal(start_event, StreamState(model="claude-3-sonnet"))
+    assert out[0]["type"] == "message_start"
+    assert out[0]["message"]["usage"]["input_tokens"] == 9
+    assert out[0]["message"]["usage"]["cache_read_input_tokens"] == 3
+
+
 def test_claude_error_conversion() -> None:
     n = ClaudeNormalizer()
     err_resp = {