fix: add left padding to voice memo recorder

[janicduplessis]

Summary

While recording a voice memo, the recorder had no left padding — the dotted waveform ran flush against the left edge of the sheet, while the right side (timer + stop button) was properly inset.

Changes

• AudioRecorder now applies contentInsetHorizontal as paddingStart while recording too — before, it was only applied during playback, leaving the waveform flush left while recording.

The flush-left look was on purpose at the component level — f1dd723ea added contentInsetHorizontal specifically to keep the recording waveform flush against the container edge, which presumably made sense for a container whose edge wasn't the screen edge. In the current recorder sheet it is the screen edge, so the waveform running off the edge just looks broken. If flush-left is ever wanted again, callers can pass contentInsetHorizontal per edge — no caller currently sets it.

How did I test?

• Ran the iOS app on an iPhone 17 Pro simulator, started a voice memo from the attachment sheet in a chat channel, and checked that the waveform now starts with the same inset as the right edge — both while recording and after stopping.

Risks and impact

• Safe to rollback without consulting PR author? Yes
• Affects important code area:
  • Onboarding
  • State / providers
  • Message sync
  • Channel display
  • Notifications
  • Other: voice memo recorder (visual-only)

Rollback plan

Revert this commit.

Screenshots / videos

Before (recording)	After (recording)	After (stopped)