[Release] Verify exact alarm permission UX

[jjoonleo]

Backlog ID: ISSUE-012
Source: plans/release_app_todos.md

Goal

Confirm exact alarm permission handling is appropriate for OnTime's alarm/reminder functionality.

Parallelization

Status: codex-ready

Prerequisites

• None

Acceptance criteria

• App checks exact alarm permission before scheduling exact alarms.
• Permission-denied and settings-recovery paths are tested on supported Android versions.
• User-facing copy explains why precise alarm timing is needed.
• Alarm scheduling gracefully falls back or reports permission-needed state.
• Relevant tests are added or updated where practical.

Codex thread guidance

• Work only on this issue's scope.
• Do not modify unrelated release issues.
• If this issue is blocked by external access or human approval, prepare the needed checklist/text and leave the issue open.
• This issue is intended to be safe for an independent Codex thread now.