v0.8.66: Ship Hotbar hidden by default until setup opt-in

[Hmbown]

Product decision

Hotbar should not appear by default in v0.8.66. The feature can remain available through /hotbar, /hotbar on, and explicit config, but a clean install with no Hotbar config should render no Hotbar panel.

This keeps v0.8.66 focused on reliability and avoids introducing another visible customization surface before the broader setup experience is ready.

Desired behavior

• Fresh config / no Hotbar key: Hotbar is hidden by default.
• Explicit hotbar = []: Hotbar remains hidden.
• Explicit [[hotbar]] bindings: Hotbar renders those bindings.
• /hotbar still opens the setup/customization surface.
• /hotbar on can restore/enable the recommended defaults for users who want it before v0.8.68.
• Existing users with explicit Hotbar config should not lose their bindings.

v0.8.68 follow-up

In v0.8.68, the setup wizard can introduce Hotbar as an optional opt-in personalization step. Users should choose whether to add it; the wizard should not silently enable it.

Acceptance criteria

• No Hotbar config does not show the Hotbar panel.
• Explicit empty config still means disabled.
• Explicit bindings still render and dispatch normally.
• /hotbar, /hotbar off, and /hotbar on behavior remains clear and tested.
• Docs/help copy says Hotbar is optional and can be enabled/configured with /hotbar.