refactor(frontend): decompose ConfigPage into dedicated config components

- Extract tab components: JailsTab, ActionsTab, FiltersTab, JailFilesTab,
  GlobalTab, ServerTab, ConfFilesTab, RegexTesterTab, MapTab, ExportTab
- Add form components: JailFileForm, ActionForm, FilterForm
- Add AutoSaveIndicator, RegexList, configStyles, and barrel index
- ConfigPage now composes these components; greatly reduces file size
- Add tests: ConfigPage.test.tsx, useAutoSave.test.ts

frontend/src/components/config/index.ts

@@ -0,0 +1,28 @@
+/**
+ * Barrel export for all config page components.
+ *
+ * Import from this module to access any component in the config package:
+ *   import { FiltersTab, RegexList } from "../components/config";
+ */
+
+export { ActionsTab } from "./ActionsTab";
+export { ActionForm } from "./ActionForm";
+export type { ActionFormProps } from "./ActionForm";
+export { AutoSaveIndicator } from "./AutoSaveIndicator";
+export type { AutoSaveStatus, AutoSaveIndicatorProps } from "./AutoSaveIndicator";
+export { ConfFilesTab } from "./ConfFilesTab";
+export type { ConfFilesTabProps } from "./ConfFilesTab";
+export { ExportTab } from "./ExportTab";
+export { FilterForm } from "./FilterForm";
+export type { FilterFormProps } from "./FilterForm";
+export { FiltersTab } from "./FiltersTab";
+export { GlobalTab } from "./GlobalTab";
+export { JailFilesTab } from "./JailFilesTab";
+export { JailFileForm } from "./JailFileForm";
+export { JailsTab } from "./JailsTab";
+export { MapTab } from "./MapTab";
+export { RegexList } from "./RegexList";
+export type { RegexListProps } from "./RegexList";
+export { RegexTesterTab } from "./RegexTesterTab";
+export { ServerTab } from "./ServerTab";
+export { useConfigStyles } from "./configStyles";