ui: Add MCP Servers Opt-In for first time visitors (#25239)

* feat: ui: Add predefined recommended MCP servers to settings

* feat: ui: Add MCP server recommendation dialog with custom server support

* feat: Auto-focus input fields on mount and dynamic addition

* feat: Add header validation to MCP server add and edit forms

* feat: Persist recommended MCP server opt-in selections

* test: Cover MCP configuration with tests

* chore: Format & cleanup

* feat: Centralize MCP server overrides to settings config and improve recommendation UI

* fix: Capture index before mutation to prevent focus drift

* refactor: Extract MCP_CARD_VISIBLE_TOOL_LIMIT to shared constants

* refactor: Support arbitrary authorization header schemes

* refactor: Consolidate MCP recommendations dismissal into existing storage key

* fix: Use case-insensitive comparison for MCP server ID prefix check

* refactor: Centralize MCP server visibility logic and extract recommendations hook

* refactor: Cleanup

tools/ui/src/lib/constants/settings-keys.ts

@@ -59,6 +59,7 @@ export const SETTINGS_KEYS = {
 	// MCP
 	MCP_SERVERS: 'mcpServers',
 	MCP_REQUEST_TIMEOUT_SECONDS: 'mcpRequestTimeoutSeconds',
+	MCP_DEFAULT_SERVER_OVERRIDES: 'mcpDefaultServerOverrides',
 	AGENTIC_MAX_TURNS: 'agenticMaxTurns',
 	ALWAYS_SHOW_AGENTIC_TURNS: 'alwaysShowAgenticTurns',
 	AGENTIC_MAX_TOOL_PREVIEW_LINES: 'agenticMaxToolPreviewLines',