fix: remove audio pause during zero-delay verse transitions

[Mubashir78]

Problem

During repeat mode playback, the audio player always pauses before seeking to the next verse, even when the delay between verses is set to zero. This creates an audible gap (voice cutoff) at verse boundaries.

The issue is in the REPEAT_AYAH action of the audio player state machine, which unconditionally calls pauseAudio before setAudioPlayerCurrentTime.

Root Cause

In audioPlayerMachine.ts, the REPEAT_AYAH transition in PLAYING.ACTIVE state always:

1. Pauses the audio element (pauseAudio)
2. Seeks to the next verse timestamp (setAudioPlayerCurrentTime)
3. Transitions to DELAYING state

Even when verseDelay === 0 (no configured delay), the pause creates a brief silence between verses.

Fix

Split the REPEAT_AYAH transition into two guarded paths:

• When verseDelay > 0: Preserves existing behavior (pause, seek, go to DELAYING state) for users who configured a delay between verses.
• When verseDelay === 0: Skips the pause entirely and seeks directly to the next verse timestamp while audio keeps playing, going straight back to PLAYING.ACTIVE. This produces seamless transitions with no voice cutoff.

Changes

src/xstate/actors/audioPlayer/audioPlayerMachine.ts:

• Split REPEAT_AYAH handler from a single transition into two guarded transitions
• Added hasVerseDelay guard: (context, event) => event.verseDelay > 0
• First transition (with guard): preserves pause + seek + DELAYING for delay > 0
• Second transition (fallback): seek only, no pause, stays in PLAYING.ACTIVE

Testing

Standalone state machine tests verified all assertions pass:

1. verseDelay > 0: machine pauses audio and enters DELAYING state
2. verseDelay === 0: machine skips pause and stays in PLAYING.ACTIVE
3. Multiple consecutive transitions with zero delay: no pauses, all seamless
4. Ayah number and seek time correctly updated in all cases