This PR groups the TUI fixes that restore macOS Terminal usability and clean up the theme/composer regressions:
- copy transcript selections on macOS drag-release so Terminal.app users can copy while mouse tracking is enabled
- copy composer selections on macOS drag-release; composer selection is internal to TextInput and does not use the global Ink selection bus
- keep IDE Cmd+C forwarding setup macOS-only, and make keybinding conflict checks respect simple when-clause overlap/negation
- force truecolor before chalk initializes (unless NO_COLOR / FORCE_COLOR / HERMES_TUI_TRUECOLOR opt-outs apply) so the default banner keeps its gold/amber/bronze gradient in Terminal.app
- move TUI surfaces onto semantic theme tokens and preserve skin prompt symbols as bare tokens with renderer-owned spacing
- render focused placeholders as dim hint text in TTY mode instead of inverse/selected-looking synthetic cursor text
Adds a minimal hand-rolled highlighter for ts/js/jsx/tsx, py, sh/bash, go, rust,
json, yaml, sql. Recognizes whole-line comments, single/double/backtick strings,
numbers, and per-language keyword sets. Unknown langs fall through to the current
plain rendering; the existing diff-specific colorization is preserved.
Closes the §8 "Markdown syntax highlighting is missing (only diff gets colored)"
finding from the TUI v2 audit without pulling in a highlighter library.
