chore(web): upgrade ESLint and plugins, simplify linting configuration

- Update eslint from ^9.18.0 to ^9.36.0
- Update eslint plugins:
  - eslint-plugin-svelte: ^3.9.0 → ^3.12.4
  - eslint-plugin-unicorn: ^60.0.0 → ^61.0.2
  - svelte-eslint-parser: ^1.2.0 → ^1.3.3
  - typescript-eslint: ^8.28.0 → ^8.45.0
- Remove eslint-p dependency in favor of native eslint concurrency
- Add unicorn/no-array-sort rule exception
- Update linting scripts to use eslint's native --concurrency flag
- Update Makefile and mise.toml to reflect simplified lint commands
- Update GitHub Actions workflow to use standard pnpm lint command

web/src/lib/managers/theme-manager.svelte.ts

@@ -67,11 +67,7 @@ class ThemeManager {
     const theme: ThemeSetting =
       value === 'system' ? { system: true, value: getDefaultTheme() } : { system: false, value };
 
-    if (theme.value === Theme.LIGHT) {
-      document.documentElement.classList.remove('dark');
-    } else {
-      document.documentElement.classList.add('dark');
-    }
+    document.documentElement.classList.toggle('dark', !(theme.value === Theme.LIGHT));
 
     this.#theme.current = theme;