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>

Cargo.toml

@@ -8,14 +8,14 @@ name = "tui-wm"
 path = "src/main.rs"
 
 [dependencies]
-crossterm = { version = "0.28", features = ["event-stream"] }
-ratatui = "0.29"
+crossterm = { version = "0.29", features = ["event-stream"] }
+ratatui = "0.30"
 serde = { version = "1", features = ["derive"] }
 serde_json = "1"
 toml = "0.8"
 toml_edit = "0.22"
-portable-pty = "0.8"
-vt100 = "0.15"
+portable-pty = "0.9"
+vt100 = "0.16"
 anyhow = "1"
 image = { version = "0.25", default-features = false, features = ["jpeg", "png", "gif", "bmp", "webp"] }
 libc = "0.2"