feat: 8 AI providers, rich text editor, agent notifications, UI contrast & font settings

- Add DeepSeek, OpenRouter, Mistral, Z.AI, LM Studio as AI providers
  with editable model names via Combobox in admin settings
- Fix OpenRouter broken by normalizeProvider bug in config.ts
- Convert agent-created notes from Markdown to HTML (TipTap rich text)
- Add Notification model + in-app notifications for agent results
- Agent notification click opens the created note directly
- Add note count display on notebook and inbox headers
- Fix checklist toggle in card view (persist state via localCheckItems)
- Add checklist creation option in tabs/list view (dropdown on + button)
- Fix image description ENOENT error with HTTP fallback
- Improve UI contrast across all themes (input, border, checkbox visibility)
- Add font family setting (Inter vs System Default) in Appearance settings
- Fix CSS font-sans variable conflict (removed dead Geist references)
- Update README with new features and 8 providers

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

memento-note/components/theme-initializer.tsx

@@ -5,9 +5,10 @@ import { useEffect } from 'react'
 interface ThemeInitializerProps {
     theme?: string
     fontSize?: string
+    fontFamily?: string
 }
 
-export function ThemeInitializer({ theme, fontSize }: ThemeInitializerProps) {
+export function ThemeInitializer({ theme, fontSize, fontFamily }: ThemeInitializerProps) {
     useEffect(() => {
 
         // Helper to apply theme
@@ -77,7 +78,20 @@ export function ThemeInitializer({ theme, fontSize }: ThemeInitializerProps) {
         }
 
         applyFontSize(fontSize)
-    }, [theme, fontSize])
+
+        // Apply font family
+        const localFontFamily = localStorage.getItem('font-family')
+        const effectiveFontFamily = localFontFamily || fontFamily || 'inter'
+        const root = document.documentElement
+        if (effectiveFontFamily === 'system') {
+            root.classList.add('font-system')
+        } else {
+            root.classList.remove('font-system')
+        }
+        if (!localFontFamily && fontFamily) {
+            localStorage.setItem('font-family', fontFamily)
+        }
+    }, [theme, fontSize, fontFamily])
 
     return null
 }