fix(capture): connect deltacast growing-master filtergraph (split output 1 unconnected)

The growing-master ffmpeg orchestrator declared split=2[vhi][vlo] but only
consumed [vlo] inside the `if (hlsDir)` block. For deltacast sources the
caller passed hlsDir=null (the ternary only matched sourceType==='sdi'), so
[vlo] was left unconnected → ffmpeg aborted with "Filter 'split' has output 1
(vlo) unconnected" / "Error binding filtergraph inputs/outputs" → 0 frames →
no HLS → "playback failed" on all deltacast previews.

Fix:
- Pass sdiHlsDir for deltacast as well as sdi (deltacast also produces the
  2nd-output HLS preview from the single SDI read).
- Make the orchestrator filter_complex conditional: split=2[vhi][vlo] when an
  HLS dir is present, split=1[vhi] (master only) otherwise, so no split output
  is ever orphaned regardless of source type.

Restores deltacast growing-master capture (master MXF + HLS preview). No poster
tap (the incomplete recorder-thumbnails poster on the deploy node added an
mjpeg output that destabilised the shared ffmpeg; tracked separately on the
feature/recorder-thumbnails branch).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

services/capture/src/capture-manager.js

@@ -689,9 +689,16 @@ class CaptureManager {
     // (which would otherwise abort the video/audio outputs and produce nothing).
     const ff = ['ffmpeg', '-y', '-hide_banner', '-loglevel', 'warning', '-stats'];
     // SDI input is interlaced; yadif then split into the master + preview taps.
+    // When there's an HLS dir we split the decode into the master ([vhi]) and
+    // the H.264 preview ([vlo]); with no HLS dir, split=1 (master only) so no
+    // split output is ever left unconnected (deltacast growing master had no
+    // HLS dir, leaving [vlo] orphaned -> 'split output 1 (vlo) unconnected').
+    const filterComplex = hlsDir
+      ? '[0:v]yadif=mode=1:deint=1,split=2[vhi][vlo]'
+      : '[0:v]yadif=mode=1:deint=1,split=1[vhi]';
     const ffArgs = [
       ...inputArgs,
-      '-filter_complex', '[0:v]yadif=mode=1:deint=1,split=2[vhi][vlo]',
+      '-filter_complex', filterComplex,
       // (a) MPEG-2 422 elementary video → "$VF"
       '-map', '[vhi]',
       ...GROWING_VIDEO_ELEMENTARY_ARGS,
@@ -982,7 +989,7 @@ exit "$BMXRC"
         framerate,
         audioChannels,
         outPath: growingPath,
-        hlsDir: (sourceType === 'sdi') ? sdiHlsDir : null,
+        hlsDir: (sourceType === 'sdi' || sourceType === 'deltacast') ? sdiHlsDir : null,
         videoCodec,
         audioMap,
       });