Feat/settings page redesign (#104)

* include credentials on login fetch requests, allows set header response

* Add theme composable and utility improvements

- Create useTheme composable for centralized theme management
- Update main.ts to use useTheme for initialization
- Generalize getCookie utility in user module
- Add utility functions for data formatting

* Add Plex integration composables and icons

- Create usePlexAuth composable for Plex OAuth flow
- Create usePlexApi composable for Plex API interactions
- Create useRandomWords composable for password generation
- Add Plex-related icons (IconPlex, IconServer, IconSync)
- Add Plex helper utilities
- Update API with Plex-related endpoints

* Add storage management components for data & privacy section

- Create StorageManager component for browser storage overview
- Create StorageSectionBrowser for localStorage/sessionStorage/cookies
- Create StorageSectionServer for server-side data (mock)
- Create ExportSection for data export functionality
- Refactor DataExport component with modular sections
- Add storage icons (IconCookie, IconDatabase, IconTimer)
- Implement collapsible sections with visual indicators
- Add colored borders per storage type
- Display item counts and total size in headers

* Add theme, password, and security settings components

- Create ThemePreferences with visual theme selector
- Create PasswordGenerator with passphrase and random modes
- Create SecuritySettings wrapper for password management
- Update ChangePassword to work with new layout
- Implement improved slider UX with visual feedback
- Add theme preview cards with gradients
- Standardize component styling and typography

* Add Plex settings and authentication components

- Create PlexSettings component for Plex account management
- Create PlexAuthButton with improved OAuth flow
- Create PlexServerInfo for server details display
- Use icon components instead of inline SVGs
- Add sync and unlink functionality
- Implement user-friendly authentication flow

* Redesign settings page with two-column layout and ProfileHero

- Create ProfileHero component with avatar and user info
- Create RequestHistory component for Plex requests (placeholder)
- Redesign SettingsPage with modern two-column grid layout
- Add shared-settings.scss for consistent styling
- Organize sections: Appearance, Security, Integrations, Data & Privacy
- Implement responsive mobile layout
- Standardize typography (h2: 1.5rem, 700 weight)
- Add compact modifier for tighter sections

src/scss/shared-settings.scss

@@ -0,0 +1,30 @@
+@import "./media-queries.scss";
+
+.settings-section-card {
+  padding: 0.85rem;
+  background-color: var(--background-ui);
+  border-radius: 0.25rem;
+  border-left: 3px solid var(--highlight-color);
+
+  @include mobile-only {
+    padding: 0.75rem;
+  }
+}
+
+.settings-section-header {
+  margin-bottom: 1rem;
+
+  h2 {
+    margin: 0 0 0.5rem 0;
+    font-size: 1.5rem;
+    font-weight: 700;
+    color: var(--text-color);
+  }
+
+  p {
+    margin: 0;
+    color: var(--text-color-70);
+    font-size: 0.95rem;
+    line-height: 1.6;
+  }
+}