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/en.ts

@@ -1103,7 +1103,6 @@ export const dict = {
   'helpDialog.section.panels': 'Panels',
   'helpDialog.section.interface': 'Interface',
   'helpDialog.item.openCommandPalette': 'Open Command Palette',
-  'helpDialog.item.quickOpenFile': 'Quick open file',
   'helpDialog.item.showKeyboardShortcuts': 'Show Keyboard Shortcuts (this dialog)',
   'helpDialog.item.toggleSessionSidebar': 'Toggle Session Sidebar',
   'helpDialog.item.cycleAgent': 'Cycle Agent (chat input)',
@@ -1586,68 +1585,20 @@ export const dict = {
   'chat.messageBody.shellCommand.showOutput': 'Show output',
   'chat.messageBody.shellCommand.copied': 'Copied',
   'chat.messageBody.shellCommand.copyOutput': 'Copy output',
-  'commandPalette.input.placeholder': 'Type a command or search...',
+  'commandPalette.title': 'Command Palette',
+  'commandPalette.description': 'Search files, sessions, and commands.',
+  'commandPalette.input.placeholder': 'Search files, sessions, commands...',
   'commandPalette.empty.noResults': 'No results found.',
-  'commandPalette.section.sessions': 'Sessions',
-  'commandPalette.section.view': 'View',
-  'commandPalette.section.theme': 'Theme',
-  'commandPalette.section.settings': 'Settings',
-  'commandPalette.section.recentSessions': 'Recent Sessions',
-  'commandPalette.item.quickOpen': 'Quick Open',
+  'commandPalette.empty.searchingFiles': 'Searching files...',
   'commandPalette.item.newSession': 'New Session',
   'commandPalette.item.newWorktreeDraft': 'New Worktree Draft',
   'commandPalette.item.showSessionSwitcher': 'Show Session Switcher',
   'commandPalette.item.toggleSidebar': 'Toggle Sidebar',
   'commandPalette.item.toggleRightSidebar': 'Toggle Right Sidebar',
-  'commandPalette.item.showGitRightSidebar': 'Show Git in Right Sidebar',
-  'commandPalette.item.showFilesRightSidebar': 'Show Files in Right Sidebar',
   'commandPalette.item.showContextUsage': 'Show Context Usage',
-  'commandPalette.item.showPlan': 'Show Plan',
   'commandPalette.item.toggleTerminal': 'Toggle Terminal',
-  'commandPalette.item.collapseTerminal': 'Collapse Terminal',
-  'commandPalette.item.expandTerminal': 'Expand Terminal',
-  'commandPalette.item.keyboardShortcuts': 'Keyboard Shortcuts',
-  'commandPalette.item.themeLight': 'Light',
-  'commandPalette.item.themeDark': 'Dark',
-  'commandPalette.item.themeSystem': 'System',
   'commandPalette.item.openSettings': 'Open Settings...',
   'commandPalette.session.untitled': 'Untitled Session',
-  'commandPalette.settingsGroup.appearance': 'Appearance',
-  'commandPalette.settingsGroup.projects': 'Projects',
-  'commandPalette.settingsGroup.general': 'General',
-  'commandPalette.settingsGroup.opencode': 'OpenChamber',
-  'commandPalette.settingsGroup.git': 'Git',
-  'commandPalette.settingsGroup.skills': 'Skills',
-  'commandPalette.settingsGroup.usage': 'Usage',
-  'commandPalette.settingsGroup.advanced': 'Advanced',
-  'commandPalette.settingsPage.home': 'Home',
-  'commandPalette.settingsPage.projects': 'Projects',
-  'commandPalette.settingsPage.remoteInstances': 'Remote Instances',
-  'commandPalette.settingsPage.providers': 'Providers',
-  'commandPalette.settingsPage.usage': 'Usage',
-  'commandPalette.settingsPage.agents': 'Agents',
-  'commandPalette.settingsPage.commands': 'Commands',
-  'commandPalette.settingsPage.mcp': 'MCP',
-  'commandPalette.settingsPage.skillsInstalled': 'Installed Skills',
-  'commandPalette.settingsPage.skillsCatalog': 'Skills Catalog',
-  'commandPalette.settingsPage.git': 'Git',
-  'commandPalette.settingsPage.appearance': 'Appearance',
-  'commandPalette.settingsPage.chat': 'Chat',
-  'commandPalette.settingsPage.shortcuts': 'Keyboard Shortcuts',
-  'commandPalette.settingsPage.sessions': 'Sessions',
-  'commandPalette.settingsPage.magicPrompts': 'Magic Prompts',
-  'commandPalette.settingsPage.notifications': 'Notifications',
-  'commandPalette.settingsPage.voice': 'Voice',
-  'commandPalette.settingsPage.tunnel': 'Remote Tunnel',
-  'quickOpenDialog.title': 'Quick Open',
-  'quickOpenDialog.description': 'Quickly open a file in the current project.',
-  'quickOpenDialog.input.placeholder': 'Search files...',
-  'quickOpenDialog.empty.openProjectFirst': 'Open a project first',
-  'quickOpenDialog.empty.searchingFiles': 'Searching files...',
-  'quickOpenDialog.empty.noMatchingFiles': 'No matching files found',
-  'quickOpenDialog.empty.noMatchingRecentFiles': 'No recent files found',
-  'quickOpenDialog.group.files': 'Files',
-  'quickOpenDialog.group.recentFiles': 'Recent Files',
   'openCodeStatusDialog.title': 'OpenCode Status',
   'openCodeStatusDialog.description': 'Inspect current OpenCode status and diagnostics.',
   'openCodeStatusDialog.actions.copy': 'Copy',