fix(rewrite): make image upload non-fatal and add rewrite tracing logs

- wordpress.py: catch image download/upload failures and skip image
  instead of aborting the entire WP draft update
- pipeline.py: add INFO logs at each step of _do_rewrite_and_draft
  to trace OpenAI call, tag generation, and WP API call
- telegram_bot.py: add INFO logs around rewrite execution + exc_info
  on error for full traceback in logs
- repositories.py: include scheduled_publish_at in get_article_by_id

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

backend/app/wordpress.py

@@ -318,13 +318,19 @@ def publish_article_draft(article: dict[str, Any]) -> tuple[int, str | None]:
     featured_media_id = None
     selected_image_url = _selected_image_url_from_meta(article.get("meta_json"))
     if selected_image_url:
-        featured_media_id = _upload_featured_media(
-            base_url=settings.wordpress_base_url,
-            auth_header=auth,
-            image_url=selected_image_url,
-            article_title=title,
-            source_url=source_url,
-        )
+        try:
+            featured_media_id = _upload_featured_media(
+                base_url=settings.wordpress_base_url,
+                auth_header=auth,
+                image_url=selected_image_url,
+                article_title=title,
+                source_url=source_url,
+            )
+        except Exception as img_exc:
+            import logging
+            logging.getLogger(__name__).warning(
+                "Bild-Upload fehlgeschlagen (wird übersprungen): %s — %s", selected_image_url, img_exc
+            )
 
     payload = {
         "title": title,