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/lib/components/ProgressOverlay.svelte

@@ -8,17 +8,7 @@
 
   let { visible = false, percent = 0, stage = '', message = '' }: Props = $props();
 
-  // Map internal stage names to user-friendly labels
-  const stageLabels: Record<string, string> = {
-    'pipeline': 'Pipeline',
-    'loading_model': 'Loading Model',
-    'transcribing': 'Transcribing',
-    'loading_diarization': 'Loading Diarization',
-    'diarizing': 'Speaker Detection',
-    'done': 'Complete',
-  };
-
-  // Pipeline steps for the task list
+  // Pipeline steps in order
   const pipelineSteps = [
     { key: 'loading_model', label: 'Load transcription model' },
     { key: 'transcribing', label: 'Transcribe audio' },
@@ -27,17 +17,47 @@
     { key: 'merging', label: 'Merge results' },
   ];
 
-  function getStepStatus(stepKey: string, currentStage: string): 'pending' | 'active' | 'done' {
-    const stepOrder = pipelineSteps.map(s => s.key);
-    const currentIdx = stepOrder.indexOf(currentStage);
-    const stepIdx = stepOrder.indexOf(stepKey);
+  const stepOrder = pipelineSteps.map(s => s.key);
 
-    if (currentStage === 'done') return 'done';
-    if (stepIdx < currentIdx) return 'done';
-    if (stepIdx === currentIdx) return 'active';
+  // Track the highest step index we've reached (never goes backward)
+  let highestStepIdx = $state(-1);
+
+  // Map non-step stages to step indices for progress tracking
+  function stageToStepIdx(s: string): number {
+    const direct = stepOrder.indexOf(s);
+    if (direct >= 0) return direct;
+    // 'pipeline' stage appears before known steps — don't change highwater mark
+    return -1;
+  }
+
+  $effect(() => {
+    if (!visible) {
+      highestStepIdx = -1;
+      return;
+    }
+    const idx = stageToStepIdx(stage);
+    if (idx > highestStepIdx) {
+      highestStepIdx = idx;
+    }
+  });
+
+  function getStepStatus(stepIdx: number): 'pending' | 'active' | 'done' {
+    if (stepIdx < highestStepIdx) return 'done';
+    if (stepIdx === highestStepIdx) return 'active';
     return 'pending';
   }
 
+  // User-friendly display of current stage
+  const stageLabels: Record<string, string> = {
+    'pipeline': 'Initializing...',
+    'loading_model': 'Loading Model',
+    'transcribing': 'Transcribing',
+    'loading_diarization': 'Loading Diarization',
+    'diarizing': 'Speaker Detection',
+    'merging': 'Merging Results',
+    'done': 'Complete',
+  };
+
   let displayStage = $derived(stageLabels[stage] || stage || 'Processing...');
 </script>
 
@@ -50,8 +70,8 @@
       </div>
 
       <div class="steps">
-        {#each pipelineSteps as step}
-          {@const status = getStepStatus(step.key, stage)}
+        {#each pipelineSteps as step, idx}
+          {@const status = getStepStatus(idx)}
           <div class="step" class:step-done={status === 'done'} class:step-active={status === 'active'}>
             <span class="step-icon">
               {#if status === 'done'}