feat(backends,jobs,telegram,conversations): mcp calls carry the conversation origin, quiet branches close asleep, fresh topics get named

tests/test_claude_sdk_backend.py

@@ -250,7 +250,11 @@ async def test_stream_envelope_and_index_rebase(cwd: Path) -> None:
     assert opts.strict_mcp_config is True
     assert opts.permission_mode == "bypassPermissions"
     assert opts.mcp_servers == {
-        "firefly": {"type": "http", "url": "http://127.0.0.1:1/mcp/firefly/"}
+        "firefly": {
+            "type": "http",
+            "url": "http://127.0.0.1:1/mcp/firefly/",
+            "headers": {"X-Conversation-Origin": "conv-1"},
+        }
     }
     assert opts.session_store is not None
     assert opts.resume is None