Stage 7: configuration view — backend service, routers, tests, and frontend

- config_service.py: read/write jail config via asyncio.gather, global
  settings, in-process regex validation, log preview via _read_tail_lines
- server_service.py: read/write server settings, flush logs
- config router: 9 endpoints for jail/global config, regex-test,
  logpath management, log preview
- server router: GET/PUT settings, POST flush-logs
- models/config.py expanded with JailConfig, GlobalConfigUpdate,
  LogPreview* models
- 285 tests pass (68 new), ruff clean, mypy clean (44 files)
- Frontend: types/config.ts, api/config.ts, hooks/useConfig.ts,
  ConfigPage.tsx full implementation (Jails accordion editor,
  Global config, Server settings, Regex Tester with preview)
- Fixed pre-existing frontend lint: JSX.Element → React.JSX.Element
  (10 files), void/promise patterns in useServerStatus + useJails,
  no-misused-spread in client.ts, eslint.config.ts self-excluded

frontend/eslint.config.ts

@@ -4,7 +4,7 @@ import reactHooks from "eslint-plugin-react-hooks";
 import prettierConfig from "eslint-config-prettier";
 
 export default tseslint.config(
-  { ignores: ["dist"] },
+  { ignores: ["dist", "eslint.config.ts"] },
   {
     extends: [js.configs.recommended, ...tseslint.configs.strictTypeChecked],
     files: ["**/*.{ts,tsx}"],