feat(PROJ-44): ocr_status/ocr_chars in MailDetail + v1 API

GET /api/mails/{id} liefert jetzt ocr_status + ocr_chars fuer das GUI-
Badge und den konditionalen Download-Button. Die externe v1-API
(/api/v1/mails/{id}) bekommt zusaetzlich ocr_status, damit CRM-
Integrationen entscheiden koennen, ob ein OCR-Text-Pull lohnt.

internal/api/v1_handlers.go

@@ -244,6 +244,13 @@ func (s *Server) handleV1GetMail(w http.ResponseWriter, r *http.Request) {
 		dateStr = pm.Date.UTC().Format(time.RFC3339)
 	}
 
+	// PROJ-44: expose ocr_status to external API consumers as well so CRM
+	// integrations can decide whether to ask for ocr-text downloads.
+	ocrStatus, _, _ := s.store.GetOCRMeta(r.Context(), id)
+	if ocrStatus == "" {
+		ocrStatus = "pending"
+	}
+
 	writeJSON(w, http.StatusOK, map[string]interface{}{
 		"id":          id,
 		"from":        pm.From,
@@ -254,6 +261,7 @@ func (s *Server) handleV1GetMail(w http.ResponseWriter, r *http.Request) {
 		"size":        len(raw),
 		"body_plain":  pm.TextBody,
 		"attachments": attachments,
+		"ocr_status":  ocrStatus,
 	})
 }