feat(tui): highlight Bash commands - #42214

What

Highlight Bash syntax wherever commands are shown or edited in the TUI:

• ! Shell-mode prompt input while the user types
• agent shell tool commands in inline and expanded tool views

Keywords, strings, variables, comments, and punctuation use the active TUI syntax theme.

How

• packages/tui/src/component/prompt/index.tsx parses Shell-mode input as Bash after edits and applies the resulting theme styles directly to the textarea edit buffer. Stale asynchronous parser results are discarded, and highlights are removed when the input changes or Shell mode closes.
• packages/tui/src/routes/session/index.tsx renders submitted Shell-mode commands and agent shell commands with the native <code filetype="bash"> component.
• Shell output remains plain, subdued text beneath the highlighted command.

Scope

This changes TUI presentation only. It does not change command execution, shell selection, or tool behavior.

Testing

• Direct Tree-sitter parser probe confirmed Bash captures for keywords, strings, variables, and comments.
• bun typecheck from packages/tui
• bun run test from packages/tui (689 passed, 5 skipped)
• Prettier check and git diff --check
• Full repository push-hook typecheck (34 packages passed)
• Scripted OpenCode Drive capture exercised ordinary and compound Shell-mode input plus an actual agent shell tool call

Demo

Shell-mode editing

The recording shows ls -la, git status --short && echo "clean", and a loop with a variable and comment.

Agent shell tool call

The recording shows an actual agent shell tool call with highlighted command syntax and real shell output.