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/provider/envelope.py

@@ -0,0 +1,267 @@
+"""Provider request/response envelope hooks.
+
+Some upstreams expose an API that is *almost* compatible with an existing
+endpoint signature (family:kind), but wrap the wire format in an extra envelope
+or require small transport-level behaviors.
+
+This module provides a small hook mechanism so handlers can stay generic while
+provider-specific envelopes live in their own service modules.
+"""
+
+from __future__ import annotations
+
+import importlib
+import threading
+from collections.abc import Iterable
+from typing import Any, Protocol
+
+
+class ProviderEnvelope(Protocol):
+    """Provider-specific envelope transformation and side-effects."""
+
+    name: str
+
+    def extra_headers(self) -> dict[str, str] | None:
+        """Extra upstream request headers to merge into the RequestBuilder."""
+
+    def wrap_request(
+        self,
+        request_body: dict[str, Any],
+        *,
+        model: str,
+        url_model: str | None,
+        decrypted_auth_config: dict[str, Any] | None,
+    ) -> tuple[dict[str, Any], str | None]:
+        """Wrap request payload and optionally override url_model (e.g. move model into body)."""
+
+    def unwrap_response(self, data: Any) -> Any:
+        """Unwrap upstream response payload (streaming chunk or full JSON)."""
+
+    def postprocess_unwrapped_response(self, *, model: str, data: Any) -> None:
+        """Best-effort post processing after unwrap (e.g. cache signatures)."""
+
+    def capture_selected_base_url(self) -> str | None:
+        """Capture the base_url selected by transport layer (if any)."""
+
+    def on_http_status(self, *, base_url: str | None, status_code: int) -> None:
+        """Called after receiving upstream HTTP status code."""
+
+    def on_connection_error(self, *, base_url: str | None, exc: Exception) -> None:
+        """Called when a connection-type exception happens."""
+
+    def force_stream_rewrite(self) -> bool:
+        """Whether streaming should always go through the rewrite/conversion path."""
+
+    # ------------------------------------------------------------------
+    # Optional lifecycle hooks (checked via hasattr before calling)
+    # ------------------------------------------------------------------
+
+    def prepare_context(
+        self,
+        *,
+        provider_config: Any,
+        key_id: str,
+        user_api_key_id: str | None = None,
+        is_stream: bool,
+        provider_id: str | None = None,
+        key: Any = None,
+    ) -> str | None:
+        """Pre-wrap hook: build provider-specific request context.
+
+        Called before wrap_request(). Returns tls_profile (or None).
+        Implementations typically set contextvars that wrap_request()
+        and extra_headers() will read.
+        """
+
+    async def post_wrap_request(self, request_body: dict[str, Any]) -> None:
+        """Post-wrap hook: async processing after wrap_request().
+
+        Called after wrap_request() completes. Use for async operations
+        like distributed session control that cannot run in sync wrap_request().
+        """
+
+    def excluded_beta_tokens(self) -> frozenset[str]:
+        """Beta tokens to strip from the merged anthropic-beta header.
+
+        Called by the request builder after merging envelope extra_headers
+        with client original headers. Return an empty frozenset to keep all.
+        """
+
+    async def extract_error_text(
+        self,
+        source: Any,
+        *,
+        limit: int = 4000,
+    ) -> str:
+        """Extract error text from upstream HTTP error response.
+
+        ``source`` is either an ``httpx.Response`` or ``httpx.HTTPStatusError``.
+        Default behavior (when not overridden) is handled by the caller.
+        Implementations may parse provider-specific error formats.
+        """
+
+
+# ---------------------------------------------------------------------------
+# Envelope Registry
+# ---------------------------------------------------------------------------
+# key: (provider_type, endpoint_sig) — endpoint_sig="" 表示通配
+_envelope_registry: dict[tuple[str, str], ProviderEnvelope] = {}
+
+
+def register_envelope(
+    provider_type: str,
+    endpoint_sig: str,
+    envelope: ProviderEnvelope,
+) -> None:
+    """注册 provider 特有的 envelope。
+
+    Args:
+        provider_type: 如 "antigravity"
+        endpoint_sig: 如 "gemini:cli"，传 "" 表示该 provider 的所有 endpoint
+        envelope: 实现了 ProviderEnvelope 协议的实例
+    """
+    from src.core.provider_types import normalize_provider_type
+
+    pt = normalize_provider_type(provider_type)
+    sig = str(endpoint_sig or "").strip().lower()
+    _envelope_registry[(pt, sig)] = envelope
+
+
+def get_provider_envelope(
+    *,
+    provider_type: str | None,
+    endpoint_sig: str | None,
+) -> ProviderEnvelope | None:
+    """Return envelope hooks for the given provider_type + endpoint signature."""
+    ensure_providers_bootstrapped(provider_types=[provider_type] if provider_type else None)
+
+    from src.core.provider_types import normalize_provider_type
+
+    pt = normalize_provider_type(provider_type)
+    sig = str(endpoint_sig or "").strip().lower()
+
+    if not pt:
+        return None
+
+    # 精确匹配优先，再尝试通配
+    return _envelope_registry.get((pt, sig)) or _envelope_registry.get((pt, ""))
+
+
+# ---------------------------------------------------------------------------
+# Provider Bootstrap（惰性 + 幂等）
+# ---------------------------------------------------------------------------
+# 所有 registry 共享同一个 bootstrap，首次访问任何 registry 时自动触发。
+# 不再依赖模块 import 顺序。
+_bootstrap_lock = threading.Lock()
+_bootstrap_condition = threading.Condition(_bootstrap_lock)
+_bootstrap_in_progress = False
+_bootstrapped_provider_types: set[str] = set()
+_auto_detected_provider_types: frozenset[str] | None = None
+
+_PROVIDER_PLUGIN_MODULES: dict[str, str] = {
+    "antigravity": "src.services.provider.adapters.antigravity.plugin",
+    "claude_code": "src.services.provider.adapters.claude_code.plugin",
+    "codex": "src.services.provider.adapters.codex.plugin",
+    "gemini_cli": "src.services.provider.adapters.gemini_cli.plugin",
+    "kiro": "src.services.provider.adapters.kiro.plugin",
+    "vertex_ai": "src.services.provider.adapters.vertex_ai.plugin",
+}
+
+
+def _normalize_bootstrap_targets(provider_types: Iterable[str] | None) -> set[str]:
+    from src.core.provider_types import normalize_provider_type
+
+    if provider_types is None:
+        return set()
+    if isinstance(provider_types, str):
+        provider_types = [provider_types]
+
+    targets: set[str] = set()
+    for raw in provider_types:
+        pt = normalize_provider_type(raw)
+        if pt in _PROVIDER_PLUGIN_MODULES:
+            targets.add(pt)
+    return targets
+
+
+def _discover_active_provider_types() -> set[str]:
+    """从数据库读取活跃 provider_type，用于按需 bootstrap。"""
+    from src.core.provider_types import normalize_provider_type
+    from src.database.database import create_session
+    from src.models.database import Provider
+
+    db = create_session()
+    try:
+        rows = (
+            db.query(Provider.provider_type).filter(Provider.is_active.is_(True)).distinct().all()
+        )
+    finally:
+        db.close()
+
+    discovered: set[str] = set()
+    for (raw_provider_type,) in rows:
+        pt = normalize_provider_type(raw_provider_type)
+        if pt in _PROVIDER_PLUGIN_MODULES:
+            discovered.add(pt)
+    return discovered
+
+
+def _bootstrap_provider_type(provider_type: str) -> None:
+    module_path = _PROVIDER_PLUGIN_MODULES[provider_type]
+    module = importlib.import_module(module_path)
+    register_all = getattr(module, "register_all", None)
+    if callable(register_all):
+        register_all()
+
+
+def ensure_providers_bootstrapped(provider_types: Iterable[str] | None = None) -> None:
+    """确保 provider plugins 已注册（幂等，支持按 provider_type 精准注册）。"""
+    global _auto_detected_provider_types, _bootstrap_in_progress  # noqa: PLW0603
+
+    targets = _normalize_bootstrap_targets(provider_types)
+
+    # DB 查询在锁外执行，避免慢查询阻塞其他线程的 bootstrap 操作。
+    need_discover = not targets and _auto_detected_provider_types is None
+    if need_discover:
+        try:
+            detected = _discover_active_provider_types()
+        except Exception:
+            detected = set()
+    else:
+        detected = set()
+
+    with _bootstrap_condition:
+        if not targets:
+            if _auto_detected_provider_types is None:
+                # 回退策略：DB 不可用/无记录时，保持原有全量 bootstrap 语义。
+                _auto_detected_provider_types = frozenset(
+                    detected if detected else _PROVIDER_PLUGIN_MODULES.keys()
+                )
+            targets = set(_auto_detected_provider_types)
+
+        while _bootstrap_in_progress:
+            _bootstrap_condition.wait()
+
+        missing = targets - _bootstrapped_provider_types
+        if not missing:
+            return
+        _bootstrap_in_progress = True
+
+    bootstrapped_now: set[str] = set()
+    try:
+        for pt in sorted(missing):
+            _bootstrap_provider_type(pt)
+            bootstrapped_now.add(pt)
+    finally:
+        with _bootstrap_condition:
+            _bootstrapped_provider_types.update(bootstrapped_now)
+            _bootstrap_in_progress = False
+            _bootstrap_condition.notify_all()
+
+
+__all__ = [
+    "ProviderEnvelope",
+    "ensure_providers_bootstrapped",
+    "get_provider_envelope",
+    "register_envelope",
+]