feat(sidebar): colored folder icons, opt-in via preferences (#124)

* feat(sidebar): colored folder icons, opt-in via preferences

* feat(sidebar): optional solid fill for colored folder icons

* feat(preferences): update description for solid folder color option

* feat(web): show folder colors on the manage documents page

* style(web): match folder color swatches to the theme color selector

* fix(web): guard theme lookup, catch color mutation errors, swatch a11y

* fix(web): serialize folder color updates and skip stale rollbacks

* fix(web): apply color-mutation race protections to icon updates

* fix(web): snapshot rollback values from the query cache

* fix(web): re-sync documents from the server after a failed icon or color update

Author: AdminTeamCoderz

apps/backend/drizzle/0006_folder_color.sql

@@ -0,0 +1 @@
+ALTER TABLE `documents` ADD `color` text;