feat: prepare frontend 1.6.0

[Priveetee]

Summary

• preserve playback progress through MSE transitions, quality changes and resume
• recover playback after iPhone and Safari tab suspension
• stop replaying the current video when autoplay is disabled
• show canonical quality labels and preserve position during quality changes
• guide gated YouTube playback to the connected-account flow
• add members-only and subscription live visibility settings
• add the notification popup preference
• update @typetype/mse to 0.1.49
• prepare Frontend version 1.6.0

Production behavior

Playback progress writes are serialized and stale cached positions expire before resume. Safari playback transitions remain bounded and require current user activation when autoplay permission has expired.

Subscription groups are not exposed in the web interface in this release.

Tests

• bun install --frozen-lockfile
• bun test
• bun run check
• bun run build
• bun run knip
• bun run sherif
• git diff --check

Rollback

Restore Frontend revision f6afc5eb.