When connected to the user's real Chrome, mgr.close() disconnected but never
closed the tabs the session opened — so every session (especially one that
failed before calling close, or a forgotten one) left its tabs piling up in the
user's browser. Idle-timeout and shutdown have the same exit path.
Track the target_ids this session creates via Target.createTarget in
`created_targets` (only ever our own tabs — never the user's existing tabs, which
the raw-CDP path attaches to, nor other sessions'). On close(), for the connected
path (not a launched browser, which Browser.close handles wholesale), close each
of those targets — the extension maps Target.closeTarget → chrome.tabs.remove.
Verified against a throwaway --cdp Chrome: open + 2 `tab new` → 3 pages; `close`
→ back to 1 (our 2 closed, the pre-existing tab untouched).
leeguooooo
e803bffbbb