Add /scotty command that displays Scotty ASCII art

[ethantao14]

Issue for this PR

Closes #

Type of change

• Bug fix
• New feature
• Refactor / code improvement
• Documentation

What does this PR do?

• adds a /scotty slash command to the interactive TUI
• it opens a dialog that prints ASCII art of Scotty the Scottish Terrier
• new file packages/tui/src/ui/dialog-scotty.tsx, modeled on the existing dialog-alert.tsx next to it
• the art is a String.raw template so the backslashes stay literal, split on newline, one text row per line
• one command object registered in packages/tui/src/app.tsx right after help.show; the slashName: "scotty" field is what actually makes /scotty work
• the ctrl+p palette and the slash autocomplete both read that same command array, so there is no second place to register it
• the Add dev container config commit is carried over from earlier setup on my fork and is not part of this feature

How did you verify your code works?

I ran the TUI locally with bun run dev and typed /scotty, and the ASCII art dialog renders as expected. Both esc and enter close it. The command also shows up in the ctrl+p command palette as "Show Scotty" under the System category, and launching it from there works too.

For static checks, oxlint is clean on both changed files and tsgo --noEmit passes for packages/tui. The package test suite passes with 193 pass, 1 skip, 0 fail.

CI is green on commit 826bb52, with unit, typecheck, and e2e smoke all succeeding.

Screenshots / recordings

Checklist

• I have tested my changes locally
• I have not included unrelated changes in this PR

If you do not follow this template your PR will be automatically rejected.

[bingbhakdibhumi]

FYI: this is the best Scotty I've seen so far today