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

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

internal/storage/voice_input_test.go

@@ -0,0 +1,24 @@
+package storage
+
+import (
+	"path/filepath"
+	"testing"
+)
+
+func TestVoiceInputChoice(t *testing.T) {
+	store, err := NewStore(filepath.Join(t.TempDir(), "voice.db"))
+	if err != nil {
+		t.Fatalf("NewStore: %v", err)
+	}
+	defer store.Close()
+	anna, _ := store.CreateUser("anna@example.com", "hash", "Anna", "member")
+	if v := store.VoiceInput(anna.ID); v != "" {
+		t.Fatalf("default should be the Whisper server (\"\"), got %q", v)
+	}
+	if err := store.SetVoiceInput(anna.ID, "browser"); err != nil || store.VoiceInput(anna.ID) != "browser" {
+		t.Fatalf("browser not stored: %v", err)
+	}
+	if err := store.SetVoiceInput(anna.ID, "google"); err == nil {
+		t.Fatal("unknown values must be refused")
+	}
+}