[Feature Request] Multiple audio clips per audio track + detach audio from video

The audio track logic is likely in the timeline component; look for audio track lane creation and the 'Add audio' affordance. The detach audio feature would involve modifying clip handling, possibly in the media or clip models. Start by exploring the codebase for audio track and video clip management to understand the current single-clip-per-lane constraint and audio-video linkage.

Description

Two related limitations in the editor's audio workflow (Cap 0.6.1, Windows):

1. A single audio track can only ever hold one audio file.
When you add an audio file, Cap places it on its own track lane. Adding another
audio file always targets an empty lane (or creates a new one) — the "Add audio"
affordance only renders while a lane is empty, so once a lane contains a segment
there is no way to add another audio clip to that same lane. This makes it
impossible to build a single "music" or "SFX" track holding several clips, or to
place two audio clips back-to-back on one lane. Every extra sound also adds a
whole new track row, which clutters the timeline in projects with several
stingers/effects.

Expected: allow multiple audio segments on one audio track — e.g. add the next
audio at the playhead on the existing lane, and allow dragging audio segments
between lanes. Other editors (Premiere, DaVinci Resolve) treat a track as a
container for many clips, not as one file per lane.

2. There is no way to detach/extract the audio from a video clip into its own
audio segment.
A recording's microphone/system audio is locked to its video clip: the clip menu
exposes volume and mute, but there is no "Detach audio"/"Unlink" action, so you
cannot move the audio independently, trim it separately from the video, or
extract the audio of an imported video into an editable audio track.

Expected: a "Detach audio" (or "Extract audio") action on clips and/or imported
media that creates an audio segment on an audio track referencing the clip's
source audio, leaving the video with its own (optionally muted) copy — matching
Premiere's "Detach Audio" / Resolve's "Detach Clip".

Reproduction

1. Open the editor for any Studio recording.
2. Click "Add track" in the timeline gutter, pick Audio, and add a music file —
   it lands on Audio 1.
3. Try to add a second audio file onto Audio 1: the lane no longer shows the
   "Add audio" affordance, and picking Audio from the track tray opens the picker
   for a new lane (Audio 2) instead.
4. Right-click the recording's video clip or an audio segment: there is no
   detach/extract audio action.

Additional Context

• Cap version: 0.6.1
• Operating system, version: Windows 11 (x64)
• Device (optional): [fill in your CPU/GPU/RAM]
• Related: #2328 (timeline/audio editing feature requests) and PR #2308
  (imported media tracks & waveforms) — this request is specifically about
  multiple clips per audio track and detaching audio from video.

Happy to split this into two separate issues if maintainers prefer.