perf: memo GridCard, fuse save fns, fix slash tab active color

memento-note/lib/consent/cookie-consent.ts

@@ -110,3 +110,58 @@ export function openCookiePreferences(): void {
   if (!isBrowser()) return
   window.dispatchEvent(new CustomEvent(OPEN_COOKIE_PREFERENCES_EVENT))
 }
+
+/**
+ * Save consent locally and sync to database for authenticated users.
+ * This is the preferred method for updating consent from UI components.
+ *
+ * Note: For server-side sync, import and call saveCookieConsent action from your component.
+ */
+export function saveConsentWithSync(analytics: boolean, marketing: boolean = false): ConsentRecord {
+  const record = setConsent({ analytics, marketing })
+
+  // Trigger server-side sync in the background
+  // The import() is dynamic to avoid "use server" import issues in client code
+  if (isBrowser()) {
+    import('@/app/actions/cookie-consent').then(({ saveCookieConsent }) => {
+      saveCookieConsent(record).catch((err) => {
+        console.warn('[saveConsentWithSync] Server sync failed (local consent saved):', err)
+      })
+    })
+  }
+
+  return record
+}
+
+/**
+ * Load consent preferring DB value when local storage is empty.
+ * For authenticated users on a new device, this syncs their existing consent.
+ *
+ * Returns the consent record that should be used, or null if no preference exists.
+ */
+export async function loadConsentWithDBSync(): Promise<ConsentRecord | null> {
+  // First check local storage (fast, always available)
+  const local = getConsent()
+  if (local) {
+    return local // User already has local preference, use it
+  }
+
+  // No local preference — try to load from DB for authenticated users
+  if (isBrowser()) {
+    try {
+      const { getCookieConsentFromDB } = await import('@/app/actions/cookie-consent')
+      const dbConsent = await getCookieConsentFromDB()
+
+      if (dbConsent) {
+        // Sync DB value to local storage for future use
+        localStorage.setItem(CONSENT_STORAGE_KEY, JSON.stringify(dbConsent))
+        writeCookie(dbConsent)
+        return dbConsent
+      }
+    } catch (error) {
+      console.warn('[loadConsentWithDBSync] Failed to load from DB:', error)
+    }
+  }
+
+  return null // No preference anywhere
+}