feat: improve terminal tool card readability and command preview by wsp1911 · Pull Request #269 · GCWing/BitFun

@wsp1911

- align TerminalToolCard running/completed output backgrounds and spacing
- match read-only xterm transparency behavior with the main terminal
- add xterm viewport/background fallback to remove bottom black bar
- soften header command text in light theme
- show full command tooltip only when the header command is truncated
- make command tooltip wrap, stay open on hover, and support text selection
- extend shared Tooltip with interactive hover behavior