Fix/remove initial alarms

[bfalls]

Fixes #56, #57

• Added notifications and exact alarms steps to the onboarding sequence with updated navigation helpers and ordering logic in the view model.
• Updated the onboarding UI to present notifications and alarms explanations with explicit Skip/Continue controls alongside consistent back/next navigation and titles.
• Wired onboarding permission actions in MainActivity to request notifications and exact alarms only when applicable, advance after results, handle exact alarm outcomes on resume, and removed post-onboarding auto prompts.
• Removed the exact alarms permission dialog and wired the onboarding Continue button to immediately launch the system Alarms & reminders settings intent while tracking pending and onboarding state transitions.
• Retained lifecycle handling so pending requests record denials or advance onboarding once exact alarm permission is granted