Address two gaps in the first DingTalk-session UI:
- add an explicit admin-only '+ 新增钉钉知识库' action on the data-source
panel; it accepts an alidocs space URL, resolves the live name/root through
the authenticated sidecar, writes the inventory root atomically, upserts a
deterministic source connection, and enqueues its first catalog refresh
- read DingTalk's real QR canvas pixels rather than taking a DOM screenshot;
select by dark-pixel content, composite onto a white quiet zone, and render
at 320x320 so the dialog contains a large complete code, not a page thumbnail
The live refresh path resolves registered roots from the connection locator,
while existing name-based DingTalk sources remain compatible.