feat: Add daily Threads content generation for manual publishing

- Add generate_threads_manual_posts() task that creates 2 posts daily
- Posts are saved with status 'draft' for manual copy/paste to Threads
- Uses tip_tech template with rotating categories (productividad, ia, etc.)
- Scheduled to run daily at 7:00 AM (Tijuana timezone)
- Posts appear in dashboard for easy access

This is a workaround while waiting for Threads API approval.

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

worker/tasks/generate_content.py

@@ -549,6 +549,84 @@ def generate_service_post(
         db.close()
 
 
+@celery_app.task(name="worker.tasks.generate_content.generate_threads_manual_posts")
+def generate_threads_manual_posts(count: int = 2):
+    """
+    Generar posts para Threads que se publicarán manualmente.
+
+    Genera tips de tecnología variados optimizados para Threads
+    y los guarda con status 'draft' para copiar y publicar manualmente.
+
+    Args:
+        count: Número de posts a generar (default 2)
+    """
+    db = SessionLocal()
+
+    try:
+        created = []
+        # Categorías para variar el contenido
+        categories = ["productividad", "ia", "seguridad", "automatización", "python", "negocios"]
+
+        for i in range(count):
+            # Seleccionar categoría diferente para cada post
+            category = categories[i % len(categories)]
+
+            # Generar contenido con IA usando el template tip_tech
+            result = run_async(
+                content_generator.generate_with_quality_check(
+                    template_name="tip_tech",
+                    variables={
+                        "category": category,
+                        "difficulty_level": "principiante",
+                        "target_audience": "profesionales y emprendedores"
+                    },
+                    platform="threads",
+                    db=db,
+                    max_attempts=2
+                )
+            )
+
+            content = result.get("content", "")
+
+            if not content:
+                logger.warning(f"No se pudo generar contenido para Threads (categoria: {category})")
+                continue
+
+            # Crear post con status draft (para publicación manual)
+            post = Post(
+                content=content,
+                content_threads=content,
+                content_type="tip_tech",
+                platforms=["threads"],
+                status="draft",  # Para publicación manual
+                approval_required=False,
+                quality_score=result.get("quality_score"),
+                score_breakdown=result.get("score_breakdown"),
+                generation_attempts=result.get("attempts", 1)
+            )
+
+            db.add(post)
+            created.append(category)
+
+        db.commit()
+
+        logger.info(f"Generados {len(created)} posts para Threads (manual): categorías={created}")
+
+        return {
+            "status": "success",
+            "generated": len(created),
+            "categories": created
+        }
+
+    except Exception as e:
+        logger.error(f"Error generando posts para Threads: {e}")
+        db.rollback()
+        return {"status": "error", "error": str(e)}
+
+    finally:
+        db.close()
+
+
 @celery_app.task(name="worker.tasks.generate_content.generate_thread")
 def generate_thread(
     topic: str,