revert(capture): remove --growing-file flag (not valid in bmx v1.6)

raw2bmx v1.6 does not have a --growing-file option; using it causes
'Unknown Input Option' and immediately crashes the pipeline. The
--part interval alone is sufficient — body partitions with updated
IndexDuration are written every 30 frames, and the file has no footer
(open state) while recording, which is what Premiere's growing-file
reader polls for.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

services/capture/src/capture-manager.js

@@ -673,7 +673,6 @@ class CaptureManager {
     // recorded duration grows mid-write.
     const bmx = [
       'raw2bmx', '-t', 'op1a', '-o', '"$OUT"', '-f', frameRate,
-      '--growing-file',
       '--part', String(GROWING_PART_INTERVAL_FRAMES),
       rawFlag, '"$VF"',
       '-s', '48000', '-q', '16', '--audio-chan', String(ach), '--pcm', '"$AF"',