feat(palette): unify quick open into command palette with multi-source search

Merge file picker into command palette. Single Cmd+P entry searches
files, sessions, settings pages and commands; groups re-order by best
fuzzy score per source. Sessions show branch labels; git status is
lazily fetched for all session directories on open.

Drop QuickOpenDialog and Cmd+K shortcut.

packages/ui/src/lib/i18n/messages/es.settings.ts

@@ -718,7 +718,6 @@ export const settingsDict = {
   "settings.openchamber.keyboardShortcuts.field.pressKeys": "Pulsa las teclas...",
   "settings.openchamber.keyboardShortcuts.error.captureFirst": "Captura un atajo primero.",
   "settings.openchamber.keyboardShortcuts.warning.riskyBrowserShortcut": "Este atajo puede entrar en conflicto con los predeterminados del navegador. Todavía se guarda.",
-  "settings.openchamber.keyboardShortcuts.action.open_quick_open.label": "Abrir búsqueda rápida",
   "settings.openchamber.keyboardShortcuts.action.open_go_to_line.label": "Ir a línea (editor de archivos)",
   "settings.openchamber.keyboardShortcuts.action.open_command_palette.label": "Abrir paleta de comandos",
   "settings.openchamber.keyboardShortcuts.action.focus_input.label": "Enfocar entrada",