feat: Focus mode — landscape flip clock + Pomodoro

[eddiegulay]

Summary

Adds Focus mode: a full-screen, landscape flip clock that doubles as a Pomodoro timer, reached deliberately by long-pressing the Home clock.

Access

• Long-press the Home clock → confirmation dialog (FocusConfirmDialog, styled like BlockConfirmDialog) → enters Focus.
• On enter, the Activity locks to landscape and hides the system bars; Back or the HOME key returns to a clean Home and restores the previous orientation (handled via a DisposableEffect and resetToHome()).

Inside Focus

Mode	Tap	Long-press
Clock	toggle seconds	→ Pomodoro
Pomodoro	start / pause	→ Clock

• Flip clock: split-flap FlipClock/FlipDigit cards in the sumi-e style; HH:MM with a tap-to-reveal seconds, driven by a new rememberSecondTime() ticker.
• Pomodoro: 25 min focus / 5 min short break / 15 min long break (every 4th focus), with reset/skip, four cycle dots, and a kanji phase label (集中 / 休憩 / 長休憩). Auto-pauses between phases.

Implementation notes

• New Screen.Focus value; rendered full-bleed outside the dock layer in TempoApp.kt.
• Navigation + confirmation state added to LauncherViewModel (requestFocus/confirmFocus/cancelFocus/goFocus).
• Home clock long-press uses pointerInput/detectTapGestures (no ripple) plus an accessibility onLongClick label.

Verification

• ./gradlew assembleDebug lintDebug testDebugUnitTest — all green locally (mirrors CI).
• Changelog updated with a ## [0.0.7] section for the release notes.

Out of scope (v1)

Configurable durations, persisting the Pomodoro across app death, sound/notification on phase end, keeping the timer alive while backgrounded.