Fix EQ/reverb double-application and blocked track state sync

[cdrani]

Summary

• Fix race condition causing EQ and reverb effects to be applied twice during audio chain initialization
• Fix blocked track state not syncing between SkipButton and TrackListSkipButton components
• Fix loop count and infinite loop functionality

Changes

Audio Effects Race Condition Fix

• Add _effectUpdateInProgress lock in media-override.ts to prevent concurrent effect updates
• Properly disconnect equalizer input/output nodes in audio-manager.ts during cleanup to prevent duplicate connections
• Remove redundant setEffect() call in track.ts since it's already triggered via REQUEST_EFFECT_REAPPLY message

Blocked Track State Sync Fix

• TrackListSkipButton now listens for both chorus:track-blocked and chorus:track-unblocked events
• Query dataStore.blocked as source of truth when handling events instead of relying on static prop values
• SkipButton now dispatches chorus:track-blocked event for proper sync with tracklist icons

Loop Count Fix

• Fix loop count logic: iteration now decrements to 0 before stopping (count=1 means loop once)
• Enable looping for full tracks, not just snipped tracks
• Handle track advancement after loop count is exhausted
• Properly separate infinite vs count-based loop handling

Test plan

• Toggle EQ presets rapidly and verify effects are applied once (no volume changes from double-application)
• Enable reverb and verify it's applied correctly without distortion
• Block a track from SkipButton and verify the Ban icon in tracklist updates to green
• Unblock from BlockedTracksDialog and verify the Ban icon in tracklist updates back to default color
• Block/unblock from TrackListSkipButton and verify BlockedTracksDialog stays in sync
• Set loop count to 1, verify track loops once then advances to next track
• Set loop count to 2, verify track loops twice then advances
• Enable infinite loop, verify track loops continuously until disabled
• Test looping on full track (no snip) and snipped track