step B.1 complete: WS context + frame schemas

app/core/ws_context.py

@@ -0,0 +1,68 @@
+"""WebSocket client executor context.
+
+Holds a per-request async callback that tools call to execute CRUD
+operations on the Electron client's local SQLite / LanceDB databases.
+The callback sends a `tool_call` WS frame and awaits the `tool_result`.
+"""
+
+from __future__ import annotations
+
+from contextvars import ContextVar
+from typing import Any, Callable, Coroutine
+from uuid import uuid4
+
+# Holds the execute callback for the current WS session.
+# Set by the chat WS handler before the orchestrator runs; cleared after.
+_client_executor: ContextVar[Callable[[dict], Coroutine[Any, Any, dict]]] = ContextVar(
+    "_client_executor"
+)
+
+
+def set_client_executor(fn: Callable[[dict], Coroutine[Any, Any, dict]]) -> None:
+    """Bind *fn* as the executor for the current async context (task/coroutine)."""
+    _client_executor.set(fn)
+
+
+def clear_client_executor() -> None:
+    """Remove the executor binding (best-effort; ContextVar resets on task exit)."""
+    try:
+        _client_executor.set(None)  # type: ignore[arg-type]
+    except Exception:
+        pass
+
+
+async def execute_on_client(
+    action: str,
+    table: str | None = None,
+    data: dict[str, Any] | None = None,
+    filters: dict[str, Any] | None = None,
+    vector: list[float] | None = None,
+    limit: int | None = None,
+) -> dict[str, Any]:
+    """Send a CRUD/vector operation to the Electron client and return the result.
+
+    Builds a ``tool_call`` payload, invokes the per-session WS callback,
+    and returns the ``tool_result`` dict from Electron.
+
+    Raises ``RuntimeError`` if no executor is set (i.e. called outside a WS session).
+    """
+    callback = _client_executor.get(None)
+    if callback is None:
+        raise RuntimeError(
+            "execute_on_client() called outside a WebSocket session — "
+            "no client executor is set."
+        )
+
+    payload: dict[str, Any] = {"id": str(uuid4()), "action": action}
+    if table is not None:
+        payload["table"] = table
+    if data is not None:
+        payload["data"] = data
+    if filters is not None:
+        payload["filters"] = {k: v for k, v in filters.items() if v is not None}
+    if vector is not None:
+        payload["vector"] = vector
+    if limit is not None:
+        payload["limit"] = limit
+
+    return await callback(payload)