feat: add thumbnail preview, audio-only detection, /download command, tests, and bugfixes

- Add thumbnail preview with metadata (title, uploader, duration) before download
- Auto-detect audio-only sites (Spotify, SoundCloud, etc.) and skip type selection
- Add /download command for feature parity with UI button
- Fix yt-dlp defer bug: StatusFailed was overwritten to StatusCompleted
- Fix handleURLInput using editText with msgID=0 (now uses sendWithKB)
- Fix filename detection: use job ID prefix for reliable file finding
- Fix double answerCb between handleBackStep and handleDownloadPrompt
- Fix runDownload unused msgID parameter
- Fix context for download goroutine (use context.Background)
- Remove unused startWebhook h parameter
- Remove dead buildToggleKeyboard function
- Add formatBytes, formatDuration, formatLabelForDisplay tests
- Add IsAudioOnlyContent, MediaType.String tests
- Add repo integration tests (users, preferences, quotas, history, delete)
- Add cmd/bot tests (parseAllowedUsers, env helpers)
- Add edge case tests for progress parser
- Add zero/negative safety guard in formatDuration
- Add .gitea, TODO.md, opencode.json to gitignore

internal/handler/handler_test.go

@@ -0,0 +1,84 @@
+package handler
+
+import (
+	"testing"
+
+	"uptodownBot/internal/domain"
+)
+
+func TestFormatBytes(t *testing.T) {
+	tests := []struct {
+		input int64
+		want  string
+	}{
+		{0, "0B"},
+		{1, "1B"},
+		{1023, "1023B"},
+		{1024, "1.0KB"},
+		{1536, "1.5KB"},
+		{1048576, "1.0MB"},
+		{1073741824, "1.0GB"},
+		{1099511627776, "1.0TB"},
+	}
+	for _, tt := range tests {
+		got := formatBytes(tt.input)
+		if got != tt.want {
+			t.Errorf("formatBytes(%d) = %q, want %q", tt.input, got, tt.want)
+		}
+	}
+}
+
+func TestFormatDuration(t *testing.T) {
+	tests := []struct {
+		input float64
+		want  string
+	}{
+		{0, "0:00"},
+		{5, "0:05"},
+		{60, "1:00"},
+		{65, "1:05"},
+		{3600, "1:00:00"},
+		{3661, "1:01:01"},
+		{86400, "24:00:00"},
+	}
+	for _, tt := range tests {
+		got := formatDuration(tt.input)
+		if got != tt.want {
+			t.Errorf("formatDuration(%f) = %q, want %q", tt.input, got, tt.want)
+		}
+	}
+}
+
+func TestFormatLabelForDisplay(t *testing.T) {
+	tests := []struct {
+		f    domain.Format
+		want string
+	}{
+		{
+			f:    domain.Format{Resolution: "1920x1080", Filesize: 1048576},
+			want: "1920x1080 (1.0MB)",
+		},
+		{
+			f:    domain.Format{Resolution: "1920x1080"},
+			want: "1920x1080",
+		},
+		{
+			f:    domain.Format{Bitrate: "128k", Filesize: 1048576},
+			want: "128k (1.0MB)",
+		},
+		{
+			f:    domain.Format{Bitrate: "128k"},
+			want: "128k",
+		},
+		{
+			f:    domain.Format{ID: "137"},
+			want: "137",
+		},
+	}
+	for _, tt := range tests {
+		got := formatLabelForDisplay(tt.f)
+		if got != tt.want {
+			t.Errorf("formatLabelForDisplay(%+v) = %q, want %q", tt.f, got, tt.want)
+		}
+	}
+}