refactor(ui): remove redundant elements and make interface coherent

[Copilot]

The main screen accumulated incoherent UI leftovers — dead views, unicode-glyph "icons" in button labels, a view switcher that never indicated the active view, and metric cards that ignored dark mode. This cleans up the interface into a coherent fitness-recording UI (net −64 lines), following the Ponytail agent rules.

Dead UI removed

• recordingIndicator ("● REC"): only ever set to GONE, never shown — deleted from both portrait/landscape layouts and SessionStateMachine.
• btnWorkoutPause: present in both layouts but never referenced from any Kotlin code — deleted.

Real icons instead of text glyphs

• Stripped ▶ Start, ◼ Stop, ◀ Back, ⏸ Pause glyph hacks from strings in all locales (en/es/ca).
• Added ic_play vector and used it on the Start button, replacing the incongruous clock icon (ic_time).
• Pruned six now-unused strings (recording, paused, workout_pause, workout_resume, start_session, stop_session) from all locales.

Lap/Chart switcher indicates active view

• Converted viewToggleRow to a MaterialButtonToggleGroup (single-selection, selection-required). Previously the "Lap" button always looked selected regardless of the visible view.
• All code paths (start, restore-after-rotation, user tap) now route through setWorkoutView(), which also syncs the checked button:

private fun setWorkoutView(showChart: Boolean) {
    isChartViewActive = showChart
    binding.viewToggleRow.check(if (showChart) R.id.btnViewChart else R.id.btnViewLap)
    ...
}

Dark-mode coherence

• Added values-night/colors.xml with dark-tinted metric card backgrounds and lighter accents; cards previously kept hard-coded light pastel backgrounds under the DayNight theme.
• Taught tools/lint.py language-parity check to skip non-locale values-* qualifiers (e.g. values-night, values-v31).

Also updated changelog 6.txt. Note: assembleDebug could not run in the sandbox (Google Maven blocked at AGP resolution — pre-existing, unrelated); please rely on CI for the build check. tools/lint.py passes 4/4.

[github-actions]

✅ Debug APK artifact is ready for commit 3509839 .
💾 Download APK artifact here.
Workflow run: https://github.com/duhow/ftms-bridge/actions/runs/30197643293