fix(voice): use file-size based duration for Windows audio playback

pocket-tts can produce WAV files with malformed headers (reporting
1 billion frames instead of the actual count). The previous fix used
MediaPlayer.NaturalDuration which read the bogus header, causing
playback to either hang or cut off unpredictably.

Now calculates duration directly from file size using the known
pocket-tts output format (24kHz, 16-bit, mono WAV). This is reliable
regardless of header accuracy.

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

Author: 2 people

plugins/voice/scripts/say

@@ -114,9 +114,14 @@ play_audio_file() {
     elif [[ "$(uname -o 2>/dev/null)" == "Msys" ]] || [[ -n "$MSYSTEM" ]]; then
         # Windows (Git Bash / MSYS2) - use WPF MediaPlayer with dynamic duration detection
         # SoundPlayer often routes audio to the wrong device on multi-output Windows systems
-        local winpath
+        # Calculate duration from file size (WAV headers from pocket-tts can be malformed)
+        # WAV format: (filesize - 44 header) / (sample_rate * bytes_per_sample * channels)
+        # pocket-tts outputs 24kHz, 16-bit, mono
+        local winpath filesize duration_ms
         winpath=$(cygpath -w "$file")
-        powershell.exe -NoProfile -Command "Add-Type -AssemblyName PresentationCore; \$mp = New-Object System.Windows.Media.MediaPlayer; \$mp.Open([uri]::new('file:///$winpath')); Start-Sleep -Milliseconds 500; \$mp.Play(); while (-not \$mp.NaturalDuration.HasTimeSpan) { Start-Sleep -Milliseconds 100 }; \$dur = [int](\$mp.NaturalDuration.TimeSpan.TotalMilliseconds); Start-Sleep -Milliseconds (\$dur + 500); \$mp.Close()"
+        filesize=$(stat -c%s "$file" 2>/dev/null || wc -c < "$file")
+        duration_ms=$(( (filesize - 44) * 1000 / (24000 * 2 * 1) + 1000 ))
+        powershell.exe -NoProfile -Command "Add-Type -AssemblyName PresentationCore; \$mp = New-Object System.Windows.Media.MediaPlayer; \$mp.Open([uri]::new('file:///$winpath')); Start-Sleep -Milliseconds 500; \$mp.Play(); Start-Sleep -Milliseconds $duration_ms; \$mp.Close()"
     elif command -v aplay > /dev/null 2>&1; then
         aplay -q "$file"
     elif command -v paplay > /dev/null 2>&1; then