[iamnbutler]

Remove project used to confirm with the empty-project wording and then fail with "This project still has a channel… Delete it first." The app now counts this host's channels in the project (archived ones too, as the host does) before asking:

• With channels, the dialog is titled " still has a channel" (or "channels"), says how many, and how to clear them: archive each from its ⋯ menu, delete it from the Archived group, then remove the project. It offers only OK.
• Without channels it is the same confirmation as before.
• "Don't ask again" no longer sends a project with channels straight to the refusal toast; that case always shows the dialog.

Part of #616 (the up-front channel check; the picker's ✕ placement is not in this PR). Map: ^347.

Smoke: loopback source host with its own ACE_HOME, two opened folders (busy with one channel, empty with none), headless Chromium. Channels ⋯ → Remove project… on busy showed "busy still has a channel / It has a channel, counting archived ones. Archive it from its ⋯ menu, delete it from the Archived group, then remove the project. / OK". On empty it showed the usual confirmation, and Remove project took it out of projects.json.

Built in Ace

No: made from Claude Code (a fix-train worker), with a headless Chromium for the smoke test. Dogfooding gap tracked in #5.