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/services/proxy_node/tunnel_protocol.py

@@ -0,0 +1,124 @@
+"""
+WebSocket \u96a7\u9053\u4e8c\u8fdb\u5236\u5e27\u534f\u8bae
+
+\u5e27\u683c\u5f0f:
+| stream_id (4B) | msg_type (1B) | flags (1B) | payload_len (4B) | payload (NB) |
+
+\u7528\u4e8e Aether \u4e0e aether-proxy \u4e4b\u95f4\u7684 WebSocket \u96a7\u9053\u591a\u8def\u590d\u7528\u901a\u4fe1\u3002
+"""
+
+import struct
+from enum import IntEnum
+from typing import Self
+
+_U64_MAX = (1 << 64) - 1
+
+HEADER_SIZE = 10  # 4 + 1 + 1 + 4 bytes
+
+
+class MsgType(IntEnum):
+    """\u6d88\u606f\u7c7b\u578b"""
+
+    REQUEST_HEADERS = 0x01  # Aether -> Proxy: \u8bf7\u6c42\u5143\u6570\u636e (JSON)
+    REQUEST_BODY = 0x02  # Aether -> Proxy: \u8bf7\u6c42\u4f53
+    RESPONSE_HEADERS = 0x03  # Proxy -> Aether: \u54cd\u5e94\u72b6\u6001\u7801 + headers (JSON)
+    RESPONSE_BODY = 0x04  # Proxy -> Aether: \u54cd\u5e94\u4f53\uff08\u6d41\u5f0f\u5206\u5757\uff09
+    STREAM_END = 0x05  # \u53cc\u5411: \u6d41\u7ed3\u675f
+    STREAM_ERROR = 0x06  # \u53cc\u5411: \u6d41\u9519\u8bef
+
+    PING = 0x10  # \u53cc\u5411: \u5fc3\u8df3 (stream_id=0)
+    PONG = 0x11  # \u53cc\u5411: \u5fc3\u8df3\u54cd\u5e94 (stream_id=0)
+    GOAWAY = 0x12  # \u53cc\u5411: \u4f18\u96c5\u5173\u95ed (stream_id=0)
+    HEARTBEAT_DATA = 0x13  # Proxy -> Aether: \u6307\u6807\u4e0a\u62a5
+    HEARTBEAT_ACK = 0x14  # Aether -> Proxy: \u5fc3\u8df3\u786e\u8ba4 + \u8fdc\u7a0b\u914d\u7f6e
+    NODE_STATUS = 0x15  # Tunnel relay -> Worker: \u8282\u70b9\u8fde\u63a5\u72b6\u6001\u5e7f\u64ad
+
+
+class FrameFlags:
+    """\u5e27\u6807\u5fd7\u4f4d"""
+
+    END_STREAM = 0x01
+    GZIP_COMPRESSED = 0x02
+
+
+class Frame:
+    """WebSocket \u96a7\u9053\u5e27"""
+
+    __slots__ = ("stream_id", "msg_type", "flags", "payload")
+
+    def __init__(
+        self,
+        stream_id: int,
+        msg_type: MsgType,
+        flags: int = 0,
+        payload: bytes = b"",
+    ) -> None:
+        self.stream_id = stream_id
+        self.msg_type = msg_type
+        self.flags = flags
+        self.payload = payload
+
+    def encode(self) -> bytes:
+        header = struct.pack(
+            "!IBBI",
+            self.stream_id,
+            self.msg_type,
+            self.flags,
+            len(self.payload),
+        )
+        return header + self.payload
+
+    @classmethod
+    def decode(cls, data: bytes) -> Self:
+        if len(data) < HEADER_SIZE:
+            raise ValueError(
+                f"\u5e27\u6570\u636e\u592a\u77ed: \u9700\u8981 {HEADER_SIZE} \u5b57\u8282, \u5b9e\u9645 {len(data)}"
+            )
+        stream_id, msg_type_raw, flags, payload_len = struct.unpack("!IBBI", data[:HEADER_SIZE])
+        expected_total = HEADER_SIZE + payload_len
+        if len(data) < expected_total:
+            raise ValueError(
+                f"\u5e27\u6570\u636e\u4e0d\u5b8c\u6574: \u9700\u8981 {expected_total} \u5b57\u8282, \u5b9e\u9645 {len(data)}"
+            )
+        try:
+            msg_type = MsgType(msg_type_raw)
+        except ValueError:
+            raise ValueError(f"\u672a\u77e5\u6d88\u606f\u7c7b\u578b: 0x{msg_type_raw:02x}")
+        payload = data[HEADER_SIZE:expected_total]
+        return cls(stream_id, msg_type, flags, payload)
+
+    @property
+    def is_end_stream(self) -> bool:
+        return bool(self.flags & FrameFlags.END_STREAM)
+
+    @property
+    def is_gzip(self) -> bool:
+        return bool(self.flags & FrameFlags.GZIP_COMPRESSED)
+
+    def __repr__(self) -> str:
+        return (
+            f"Frame(stream={self.stream_id}, type={self.msg_type.name}, "
+            f"flags=0x{self.flags:02x}, payload_len={len(self.payload)})"
+        )
+
+
+def normalize_heartbeat_id(value: object) -> int | None:
+    """Normalize heartbeat_id to u64-compatible int for Rust ACK parsing."""
+    if isinstance(value, bool) or value is None:
+        return None
+    parsed: int | None = None
+    if isinstance(value, int):
+        parsed = value
+    elif isinstance(value, float):
+        if value.is_integer():
+            parsed = int(value)
+    elif isinstance(value, str):
+        stripped = value.strip()
+        if stripped.isdigit():
+            try:
+                parsed = int(stripped)
+            except ValueError:
+                parsed = None
+    if parsed is None or parsed < 0 or parsed > _U64_MAX:
+        return None
+    return parsed