allozaur/feat/chat slash commands (#26716)

* base : slash-command/misc foundation - model icon and focus-selector constants

* feat : slash-command picker and command parsing helpers

* refactor : wire command and @-mention pickers into the chat form

* ui : improve model selector keyboard navigation and load/dismiss

* feat: Unify markdown/raw-text rendering under one setting with migration

* fix: Misc fixes - tool-call subtitle, assistant wrap, progress guards

* feat: Clamp and style numeric settings inputs from registry bounds

tools/ui/src/lib/constants/working-directory.ts

@@ -8,6 +8,9 @@
 
 export const GLOB_WILDCARD = '*';
 
+/** Label shown for the working-directory picker / `/cwd` slash command. */
+export const SET_WORKING_DIRECTORY_LABEL = 'Set working directory';
+
 /** Character that starts and ends a glob character-class fragment. */
 export const GLOB_RANGE_OPEN = '[';
 export const GLOB_RANGE_CLOSE = ']';