refactor: async skill compile and context sharing

api/core/sandbox/initializer/base.py

@@ -1,11 +1,41 @@
+from __future__ import annotations
+
 from abc import ABC, abstractmethod
+from dataclasses import dataclass, field
+from typing import TYPE_CHECKING
 
 from core.sandbox.sandbox import Sandbox
 
+if TYPE_CHECKING:
+    from core.app_assets.entities.assets import AssetItem
+
+
+@dataclass
+class SandboxInitializeContext:
+    """Shared identity context passed to every ``SandboxInitializer``.
+
+    Carries the common identity fields that virtually every initializer
+    needs, plus optional artefact slots that sync initializers populate
+    for async initializers to consume.
+
+    Identity fields are immutable by convention; artefact slots are
+    written at most once during the sync phase and read during the
+    async phase.
+    """
+
+    tenant_id: str
+    app_id: str
+    assets_id: str
+    user_id: str
+
+    # Populated by DraftAppAssetsInitializer (sync) for
+    # DraftAppAssetsDownloader (async) to download into the VM.
+    built_assets: list[AssetItem] | None = field(default=None)
+
 
 class SandboxInitializer(ABC):
     @abstractmethod
-    def initialize(self, sandbox: Sandbox) -> None: ...
+    def initialize(self, sandbox: Sandbox, ctx: SandboxInitializeContext) -> None: ...
 
 
 class SyncSandboxInitializer(SandboxInitializer):