fix: bugs surfaced by new gtest coverage

- html.cpp: rgba() colors parsed with setRedF/GreenF/BlueF (0-1) while the
  writer emits 0-255 integers, so semi-transparent text colors lost their
  RGB on round-trip; parse with integer setters instead
- CLIProgressDialog: percentage padding compared normalized progress
  (0.0-1.0) against 10/100, so padding was always fully applied; compute
  the percentage first
- TimelineUndoPointer BlockTrimCommand: remove_block_from_graph_ was
  never initialized (UB on redo)
- TimelineUndoGeneral TransitionRemoveCommand: track_ was never
  initialized; GetRelevantProject() could dereference it before redo()
- ProjectLoadTask::Run(): failure path deleted project_ without
  resetting it, leaving GetLoadedProject() dangling

app/cli/cliprogress/cliprogressdialog.cpp

@@ -86,15 +86,20 @@ void CLIProgressDialog::Update()
 
 	std::cout << "] ";
 
-	if (progress_ < 100) {
+	// Pad the percentage so single/double/triple digit values all occupy the
+	// same width. Note progress_ is normalized (0.0-1.0), so the percentage
+	// must be computed before comparing against 10/100.
+	const int percent = qRound(progress_ * 100.0);
+
+	if (percent < 100) {
 		std::cout << " ";
 	}
 
-	if (progress_ < 10) {
+	if (percent < 10) {
 		std::cout << " ";
 	}
 
-	std::cout << qRound(progress_ * 100.0) << "% " << std::endl << std::flush;
+	std::cout << percent << "% " << std::endl << std::flush;
 }
 
 void CLIProgressDialog::SetProgress(double p)