feat(voice): per-account choice between Whisper and the browser; STT_ALLOW_BROWSER

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

internal/config/config.go

@@ -86,6 +86,7 @@ type SpeechConfig struct {
 	Language       string
 	APIKey         string
 	Disabled       bool // STT_DISABLED=true hides voice input everywhere
+	NoBrowser      bool // STT_ALLOW_BROWSER=false forbids the browser's recognition (it sends audio to Google/Microsoft)
 	MaxSeconds     int  // recordings stop after this long (enforced in the browser)
 	MaxUploadMB    int
 	MaxParallel    int // transcriptions running at the same time; more wait in line
@@ -102,6 +103,8 @@ func (s SpeechConfig) Mode(demo bool) string {
 		return "off"
 	case s.URL != "" && !demo:
 		return "server"
+	case s.NoBrowser:
+		return "off"
 	default:
 		return "browser"
 	}
@@ -266,6 +269,7 @@ func Load() *Config {
 			Language:       getEnv("STT_LANGUAGE", "de"),
 			APIKey:         getEnv("STT_API_KEY", ""),
 			Disabled:       strings.ToLower(getEnv("STT_DISABLED", "false")) == "true",
+			NoBrowser:      strings.ToLower(getEnv("STT_ALLOW_BROWSER", "true")) == "false",
 			MaxSeconds:     envInt("STT_MAX_SECONDS", 600, 5, 3600),
 			MaxUploadMB:    envInt("STT_MAX_UPLOAD_MB", 25, 1, 500),
 			MaxParallel:    envInt("STT_MAX_PARALLEL", 1, 1, 32),