refactor: 移除 Python 后端源码，全面迁移至 Rust gateway 架构

- 删除全部 Python 源码 (src/) 及 Alembic 迁移脚本，归档至 _deprecated_py_src/
- 重构 Rust gateway ai_pipeline: 拆分 planner/finalize 模块，新增 contracts/adaptation 层
- 重组 handlers 模块为 admin/public/proxy/internal/shared 子模块结构
- 新增 executor 模块，引入 Rust 原生数据库迁移 (aether-data/migrations)
- 简化 CI/Docker 构建流程，移除 base image 二级构建，统一为单一 app image
- 移除 Python 相关基础设施文件 (entrypoint.sh, gunicorn_conf.py, Dockerfile.base)

_deprecated_py_src/models/claude.py

@@ -0,0 +1,118 @@
+from typing import Any, Literal
+
+from pydantic import BaseModel, ConfigDict
+
+
+# 配置允许额外字段，以支持API的新特性
+class BaseModelWithExtras(BaseModel):
+    model_config = ConfigDict(extra="allow")
+
+
+class ClaudeContentBlockText(BaseModelWithExtras):
+    type: Literal["text"]
+    text: str
+
+
+class ClaudeContentBlockImage(BaseModelWithExtras):
+    type: Literal["image"]
+    source: dict[str, Any]
+
+
+class ClaudeContentBlockToolUse(BaseModelWithExtras):
+    type: Literal["tool_use"]
+    id: str
+    name: str
+    input: dict[str, Any]
+
+
+class ClaudeContentBlockToolResult(BaseModelWithExtras):
+    type: Literal["tool_result"]
+    tool_use_id: str
+    content: str | list[dict[str, Any]] | dict[str, Any]
+
+
+class ClaudeContentBlockThinking(BaseModelWithExtras):
+    type: Literal["thinking"]
+    thinking: str
+
+
+class ClaudeSystemContent(BaseModelWithExtras):
+    type: Literal["text"]
+    text: str
+
+
+class ClaudeMessage(BaseModelWithExtras):
+    role: Literal["user", "assistant"]
+    # 宽松的内容类型定义 - 接受字符串或任意字典列表
+    # 作为转发代理,不应该严格限制内容块类型,以支持API的新特性
+    content: str | list[dict[str, Any]]
+
+
+class ClaudeTool(BaseModelWithExtras):
+    name: str
+    description: str | None = None
+    input_schema: dict[str, Any]
+
+
+class ClaudeThinkingConfig(BaseModelWithExtras):
+    enabled: bool = True
+
+
+class ClaudeMessagesRequest(BaseModelWithExtras):
+    model: str
+    max_tokens: int
+    messages: list[ClaudeMessage]
+    # 宽松的system类型 - 接受字符串、字典列表或任意字典
+    system: str | list[dict[str, Any]] | dict[str, Any] | None = None
+    stop_sequences: list[str] | None = None
+    stream: bool | None = False
+    temperature: float | None = 1.0
+    top_p: float | None = None
+    top_k: int | None = None
+    metadata: dict[str, Any] | None = None
+    tools: list[dict[str, Any]] | None = None  # 改为更宽松的类型
+    tool_choice: dict[str, Any] | None = None
+    thinking: dict[str, Any] | None = None  # 改为更宽松的类型
+
+
+class ClaudeTokenCountRequest(BaseModelWithExtras):
+    model: str
+    messages: list[ClaudeMessage]
+    # 宽松的类型定义以支持API新特性
+    system: str | list[dict[str, Any]] | dict[str, Any] | None = None
+    tools: list[dict[str, Any]] | None = None
+    thinking: dict[str, Any] | None = None
+    tool_choice: dict[str, Any] | None = None
+
+
+# ---------------------------------------------------------------------------
+# 响应模型
+# ---------------------------------------------------------------------------
+
+
+class ClaudeResponseUsage(BaseModelWithExtras):
+    """Claude 响应 token 使用量"""
+
+    input_tokens: int = 0
+    output_tokens: int = 0
+    cache_creation_input_tokens: int | None = None
+    cache_read_input_tokens: int | None = None
+
+
+class ClaudeResponse(BaseModelWithExtras):
+    """
+    Claude Messages API 响应模型
+
+    对应 POST /v1/messages 端点的响应体。
+    """
+
+    id: str
+    model: str
+    type: Literal["message"] = "message"
+    role: Literal["assistant"] = "assistant"
+    content: list[dict[str, Any]]
+    stop_reason: str | None = None
+    stop_sequence: str | None = None
+    usage: ClaudeResponseUsage | None = None
+    context_management: dict[str, Any] | None = None
+    container: dict[str, Any] | None = None