feat: use workspace identity for telemetry (#2371)

Co-authored-by: dadachann <185672915+dadachann@users.noreply.github.com>

src/langbot/pkg/telemetry/identity.py

@@ -0,0 +1,16 @@
+from __future__ import annotations
+
+import typing
+
+
+class WorkspaceExecutionContext(typing.Protocol):
+    @property
+    def workspace_uuid(self) -> str: ...
+
+
+def workspace_identity(execution_context: WorkspaceExecutionContext) -> dict[str, str]:
+    """Build the canonical telemetry identity for one Workspace execution."""
+    workspace_uuid = execution_context.workspace_uuid.strip()
+    if not workspace_uuid:
+        raise ValueError("Telemetry execution Workspace UUID is empty")
+    return {"workspace_uuid": workspace_uuid}