fix: auto-tagging provider resolution, email test flow, language detection

Auto-tagging:
- CRITICAL FIX: contextual-auto-tag.service.ts was calling getAIProvider()
  (alias for getEmbeddingsProvider) instead of getTagsProvider(). This meant
  auto-tagging used the embeddings provider/model instead of the tags one.
  Now correctly uses getTagsProvider() in both suggestFromExistingLabels and
  suggestNewLabels methods.
- Pass user's detected language to suggestLabels() for localized prompts
  (was hardcoded to 'en')

Email:
- Fix Resend "from" field: pass DB config to sendViaResend() instead of
  re-fetching from DB. Uses SMTP_FROM from config, with localhost-aware fallback.
- Add "Sender email" field in admin Resend section so users can set SMTP_FROM
- Save SMTP_FROM when Resend is selected (was only saved for SMTP mode)
- Test email button now saves config to DB BEFORE testing, so unsaved form
  values are used (was reading stale DB values)

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

memento-note/app/(main)/admin/settings/admin-settings-form.tsx

@@ -277,6 +277,8 @@ export function AdminSettingsForm({ config }: { config: Record<string, string> }
     if (emailProvider === 'resend') {
       const key = formData.get('RESEND_API_KEY') as string
       if (key) data.RESEND_API_KEY = key
+      const from = formData.get('SMTP_FROM') as string
+      if (from) data.SMTP_FROM = from
     } else {
       data.SMTP_HOST = formData.get('SMTP_HOST') as string
       data.SMTP_PORT = formData.get('SMTP_PORT') as string
@@ -300,6 +302,32 @@ export function AdminSettingsForm({ config }: { config: Record<string, string> }
   const handleTestEmail = async () => {
     setIsTesting(true)
     try {
+      // Save email config to DB first so test uses the latest values
+      const emailForm = document.querySelector('form[name="email-form"]') as HTMLFormElement
+      if (emailForm) {
+        const formData = new FormData(emailForm)
+        const saveData: Record<string, string> = { EMAIL_PROVIDER: emailProvider }
+        if (emailProvider === 'resend') {
+          const key = formData.get('RESEND_API_KEY') as string
+          if (key) saveData.RESEND_API_KEY = key
+          const from = formData.get('SMTP_FROM') as string
+          if (from) saveData.SMTP_FROM = from
+        } else {
+          saveData.SMTP_HOST = formData.get('SMTP_HOST') as string
+          saveData.SMTP_PORT = formData.get('SMTP_PORT') as string
+          saveData.SMTP_USER = formData.get('SMTP_USER') as string
+          saveData.SMTP_PASS = formData.get('SMTP_PASS') as string
+          saveData.SMTP_FROM = formData.get('SMTP_FROM') as string
+          saveData.SMTP_IGNORE_CERT = smtpIgnoreCert ? 'true' : 'false'
+          saveData.SMTP_SECURE = smtpSecure ? 'true' : 'false'
+        }
+        const saveResult = await updateSystemConfig(saveData)
+        if (saveResult.error) {
+          toast.error('Failed to save settings before testing: ' + saveResult.error)
+          setIsTesting(false)
+          return
+        }
+      }
       const result: any = await testEmail(emailProvider)
       if (result.success) {
         toast.success(t('admin.smtp.testSuccess'))
@@ -892,7 +920,7 @@ export function AdminSettingsForm({ config }: { config: Record<string, string> }
           <CardTitle>{t('admin.email.title')}</CardTitle>
           <CardDescription>{t('admin.email.description')}</CardDescription>
         </CardHeader>
-        <form onSubmit={(e) => { e.preventDefault(); handleSaveEmail(new FormData(e.currentTarget)) }}>
+        <form name="email-form" onSubmit={(e) => { e.preventDefault(); handleSaveEmail(new FormData(e.currentTarget)) }}>
           <CardContent className="space-y-4">
             <div className="space-y-2">
               <label className="text-sm font-medium">{t('admin.email.provider')}</label>
@@ -957,6 +985,11 @@ export function AdminSettingsForm({ config }: { config: Record<string, string> }
                   <Input id="RESEND_API_KEY" name="RESEND_API_KEY" type="password" defaultValue={config.RESEND_API_KEY || ''} placeholder="re_..." />
                   <p className="text-xs text-muted-foreground">{t('admin.resend.apiKeyHint')}</p>
                 </div>
+                <div className="space-y-2">
+                  <label htmlFor="SMTP_FROM_RESEND" className="text-sm font-medium">Sender email</label>
+                  <Input id="SMTP_FROM_RESEND" name="SMTP_FROM" defaultValue={config.SMTP_FROM || ''} placeholder="noreply@yourdomain.com" />
+                  <p className="text-xs text-muted-foreground">Email address used as sender. Must be a domain verified in Resend.</p>
+                </div>
                 {config.RESEND_API_KEY && (
                   <div className="flex items-center gap-2 text-xs text-green-600">
                     <span className="inline-block w-2 h-2 rounded-full bg-green-500" />

memento-note/app/actions/notes.ts

@@ -509,10 +509,26 @@ export async function createNote(data: {
           console.log('[BG] Auto-labeling check: enabled=', autoLabelingEnabled, 'confidence=', autoLabelingConfidence, 'notebookId=', notebookId)
 
           if (autoLabelingEnabled) {
+            // Detect user's language from their existing notes for localized prompts
+            let userLang = 'en'
+            try {
+              const langResult = await prisma.note.groupBy({
+                by: ['language'],
+                where: { userId, language: { not: null } },
+                _count: true,
+                orderBy: { _count: { language: 'desc' } },
+                take: 1,
+              })
+              if (langResult.length > 0 && langResult[0].language) {
+                userLang = langResult[0].language
+              }
+            } catch {}
+
             const suggestions = await contextualAutoTagService.suggestLabels(
               content,
               notebookId,
-              userId
+              userId,
+              userLang
             )
 
             console.log('[BG] Auto-labeling suggestions:', suggestions.length, suggestions.map(s => s.label))