Upgrade TUI stack: ratatui 0.30, crossterm 0.29, portable-pty 0.9, vt100 0.16

- Capture OSC 0/2 window title in scan_osc_sequences since vt100 0.16
  no longer exposes Screen::title()
- Remove committed build artifacts (testapps/mouse-test/target) and
  extend .gitignore

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

.gitignore

@@ -1,2 +1,4 @@
 /target
-/builds
+builds/
+logs/
+testapps/*/target