Cross-platform distribution, UI improvements, and performance optimizations

- PyInstaller frozen sidecar: spec file, build script, and ffmpeg path resolver
  for self-contained distribution without Python prerequisites
- Dual-mode sidecar launcher: frozen binary (production) with dev mode fallback
- Parallel transcription + diarization pipeline (~30-40% faster)
- GPU auto-detection for diarization (CUDA when available)
- Async run_pipeline command for real-time progress event delivery
- Web Audio API backend for instant playback and seeking
- OpenAI-compatible provider replacing LiteLLM client-side routing
- Cross-platform RAM detection (Linux/macOS/Windows)
- Settings: speaker count hint, token reveal toggles, dark dropdown styling
- Loading splash screen, flexbox layout fix for viewport overflow
- Gitea Actions CI/CD pipeline (Linux, Windows, macOS ARM)
- Updated README and CLAUDE.md documentation

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src-tauri/src/commands/transcribe.rs

@@ -73,7 +73,7 @@ pub fn download_diarize_model(hf_token: String) -> Result<Value, String> {
 
 /// Run the full transcription + diarization pipeline via the Python sidecar.
 #[tauri::command]
-pub fn run_pipeline(
+pub async fn run_pipeline(
     app: AppHandle,
     file_path: String,
     model: Option<String>,
@@ -106,25 +106,34 @@ pub fn run_pipeline(
         }),
     );
 
-    let response = manager.send_and_receive_with_progress(&msg, |msg| {
-        let event_name = match msg.msg_type.as_str() {
-            "pipeline.segment" => "pipeline-segment",
-            "pipeline.speaker_update" => "pipeline-speaker-update",
-            _ => "pipeline-progress",
-        };
-        let _ = app.emit(event_name, &msg.payload);
-    })?;
+    // Run the blocking sidecar I/O on a separate thread so the async runtime
+    // can deliver emitted events to the webview while processing is ongoing.
+    let app_handle = app.clone();
+    tauri::async_runtime::spawn_blocking(move || {
+        let response = manager.send_and_receive_with_progress(&msg, |msg| {
+            let event_name = match msg.msg_type.as_str() {
+                "pipeline.segment" => "pipeline-segment",
+                "pipeline.speaker_update" => "pipeline-speaker-update",
+                _ => "pipeline-progress",
+            };
+            if let Err(e) = app_handle.emit(event_name, &msg.payload) {
+                eprintln!("[sidecar-rs] Failed to emit {event_name}: {e}");
+            }
+        })?;
 
-    if response.msg_type == "error" {
-        return Err(format!(
-            "Pipeline error: {}",
-            response
-                .payload
-                .get("message")
-                .and_then(|v| v.as_str())
-                .unwrap_or("unknown")
-        ));
-    }
+        if response.msg_type == "error" {
+            return Err(format!(
+                "Pipeline error: {}",
+                response
+                    .payload
+                    .get("message")
+                    .and_then(|v| v.as_str())
+                    .unwrap_or("unknown")
+            ));
+        }
 
-    Ok(response.payload)
+        Ok(response.payload)
+    })
+    .await
+    .map_err(|e| format!("Pipeline task failed: {e}"))?
 }