feat: report independent instance and workspace identities (#2394)

* feat: report independent instance and workspace identities

* test: include workspace in OAuth callback fixture

* ci: pin production cloud adapter to Space release

* fix: preserve authenticated Workspace telemetry attribution

* ci: pin production cloud adapter to final Space release

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

src/langbot/pkg/workspace/entities.py

@@ -1,5 +1,6 @@
 from __future__ import annotations
 
+import datetime
 from dataclasses import dataclass
 
 
@@ -12,3 +13,4 @@ class WorkspaceExecutionBinding:
     placement_generation: int
     write_fenced: bool
     state: str
+    workspace_created_at: datetime.datetime | None = None