Summary

Bundles the latest four commits on main: installer improvements (install path normalization, remote model list / API URL parity with settings, system theme option), and removal of the onboarding page.

Changes

BitFun Installer

• Install path: Resolves the real install root to <chosen parent>/BitFun. If the user already picks a folder whose last segment is BitFun, it is not duplicated. After browse, the path is normalized via validate_install_path so the field shows the final directory immediately.
• Model setup: Remote model listing and multi-format API URL resolution aligned with the main app’s settings behavior.
• Theme: Adds a “follow system” theme option for first-launch preference.

Other

• Removes the onboarding page (chore: remove onboarding page).

Test Plan

• Installer: pick any parent folder; confirm target is .../BitFun and installation completes.
• Installer: model list and API URL behavior match the main app settings.
• Installer: system theme option persists and applies on first launch.
• App: no regressions after onboarding removal (navigation, first run).