fix(media): reject no-audio files + purge poisoned waveform cache (fix #150)

crates/opentake-agent/src/mcp/dispatch.rs

@@ -437,6 +437,7 @@ impl Dispatcher {
             opacity: a.opacity,
             transform: a.transform.map(transform_from_arg),
             text_content: a.content.clone(),
+            ..Default::default()
         };
         let res = self.apply(EditCommand::SetClipProperties {
             clip_ids,

crates/opentake-media/src/decode/pcm.rs

@@ -147,6 +147,12 @@ pub fn extract_pcm(path: &Path, spec: &PcmSpec, range: Option<(f64, f64)>) -> Re
     if !status.success() && raw.is_empty() {
         return Err(MediaError::no_track("audio", path));
     }
+    // ffmpeg can exit 0 with empty stdout when metadata says audio exists but
+    // no decodable samples: treat as no audio track so the waveform cache
+    // isn't poisoned with all-1.0 silence.
+    if raw.is_empty() {
+        return Err(MediaError::no_track("audio", path));
+    }
 
     let samples = raw_to_mono_f32(&raw, spec);
     Ok(PcmBuffer {

crates/opentake-media/src/waveform/store.rs

@@ -34,6 +34,11 @@ pub fn load_waveform(cache_root: &Path, key: &str) -> Option<Vec<f32>> {
     while let Ok(v) = cursor.read_f32::<LittleEndian>() {
         out.push(v);
     }
+    // Reject poison files: every bucket == 1.0 silence is what an older build
+    // cached when extract_pcm returned an empty Vec. Force regeneration.
+    if !out.is_empty() && out.iter().all(|&v| v == 1.0) {
+        return None;
+    }
     Some(out)
 }