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
Selected rows in the model/session/skills pickers and approval/clarify
prompts only changed from dim gray to cornsilk, which reads as low
contrast on lighter themes and LCDs (reported during TUI v2 blitz).
Switch the selected row to `inverse bold` with the brand accent color
across modelPicker, sessionPicker, skillsHub, and prompts so the
highlight is terminal-portable and unambiguous. Unselected rows stay
dim. Also extends the sessionPicker middle meta column (which was
always dim) to inherit the row's selection state.
