feat: move article generation to background worker queue

- Add generate_articles task handler to worker.py
- template_generate and template_regenerate now enqueue tasks instead
  of running inline (was blocking HTTP request for seconds with 1k articles)
- rebuild_all enqueues per-template + inline rebuilds manual articles
- Update tests to check task enqueue instead of immediate article creation

Subtask 4 of CMS admin improvement.

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

web/src/padelnomics/admin/routes.py

@@ -1314,7 +1314,7 @@ async def template_preview(slug: str, row_key: str):
 @csrf_protect
 async def template_generate(slug: str):
     """Generate articles from template + DuckDB data."""
-    from ..content import fetch_template_data, generate_articles, load_template
+    from ..content import fetch_template_data, load_template
 
     try:
         config = load_template(slug)
@@ -1330,15 +1330,20 @@ async def template_generate(slug: str):
         start_date_str = form.get("start_date", "")
         articles_per_day = int(form.get("articles_per_day", 3) or 3)
 
-        if not start_date_str:
-            start_date = date.today()
-        else:
-            start_date = date.fromisoformat(start_date_str)
+        start_date = date.fromisoformat(start_date_str) if start_date_str else date.today()
 
-        generated = await generate_articles(
-            slug, start_date, articles_per_day, limit=500,
+        from ..worker import enqueue
+        await enqueue("generate_articles", {
+            "template_slug": slug,
+            "start_date": start_date.isoformat(),
+            "articles_per_day": articles_per_day,
+            "limit": 500,
+        })
+        await flash(
+            f"Article generation queued for '{config['name']}'. "
+            "The worker will process it in the background.",
+            "success",
         )
-        await flash(f"Generated {generated} articles with staggered publish dates.", "success")
         return redirect(url_for("admin.articles"))
 
     return await render_template(
@@ -1354,7 +1359,7 @@ async def template_generate(slug: str):
 @csrf_protect
 async def template_regenerate(slug: str):
     """Re-generate all articles for a template with fresh DuckDB data."""
-    from ..content import generate_articles, load_template
+    from ..content import load_template
 
     try:
         load_template(slug)
@@ -1362,9 +1367,14 @@ async def template_regenerate(slug: str):
         await flash("Template not found.", "error")
         return redirect(url_for("admin.templates"))
 
-    # Use today as start date, keep existing publish dates via upsert
-    generated = await generate_articles(slug, date.today(), articles_per_day=500)
-    await flash(f"Regenerated {generated} articles from fresh data.", "success")
+    from ..worker import enqueue
+    await enqueue("generate_articles", {
+        "template_slug": slug,
+        "start_date": date.today().isoformat(),
+        "articles_per_day": 500,
+        "limit": 500,
+    })
+    await flash("Regeneration queued. The worker will process it in the background.", "success")
     return redirect(url_for("admin.template_detail", slug=slug))
 
 
@@ -1877,13 +1887,29 @@ async def article_rebuild(article_id: int):
 @role_required("admin")
 @csrf_protect
 async def rebuild_all():
-    """Re-render all articles."""
-    articles = await fetch_all("SELECT id FROM articles")
-    count = 0
-    for a in articles:
+    """Re-render all articles via background worker."""
+    from ..content import discover_templates
+    from ..worker import enqueue
+
+    templates = discover_templates()
+    for t in templates:
+        await enqueue("generate_articles", {
+            "template_slug": t["slug"],
+            "start_date": date.today().isoformat(),
+            "articles_per_day": 500,
+            "limit": 500,
+        })
+
+    # Manual articles still need inline rebuild
+    manual = await fetch_all("SELECT id FROM articles WHERE template_slug IS NULL")
+    for a in manual:
         await _rebuild_article(a["id"])
-        count += 1
-    await flash(f"Rebuilt {count} articles.", "success")
+
+    await flash(
+        f"Queued rebuild for {len(templates)} templates"
+        f" + rebuilt {len(manual)} manual articles.",
+        "success",
+    )
     return redirect(url_for("admin.articles"))
 
 

web/src/padelnomics/worker.py

@@ -709,6 +709,22 @@ async def handle_cleanup_seo_metrics(payload: dict) -> None:
     print(f"[WORKER] Cleaned up {deleted} old SEO metric rows")
 
 
+@task("generate_articles")
+async def handle_generate_articles(payload: dict) -> None:
+    """Generate articles from a template in the background."""
+    from datetime import date as date_cls
+
+    from .content import generate_articles
+
+    slug = payload["template_slug"]
+    start_date = date_cls.fromisoformat(payload["start_date"])
+    articles_per_day = payload.get("articles_per_day", 3)
+    limit = payload.get("limit", 500)
+
+    count = await generate_articles(slug, start_date, articles_per_day, limit=limit)
+    print(f"[WORKER] Generated {count} articles for template '{slug}'")
+
+
 # =============================================================================
 # Worker Loop
 # =============================================================================

web/tests/test_content.py

@@ -1019,7 +1019,7 @@ class TestAdminTemplateGenerate:
         assert "3" in html  # 3 rows available
         assert "Generate" in html
 
-    async def test_generate_creates_articles(self, admin_client, db, pseo_env):
+    async def test_generate_enqueues_task(self, admin_client, db, pseo_env):
         async with admin_client.session_transaction() as sess:
             sess["csrf_token"] = "test"
 
@@ -1030,11 +1030,16 @@ class TestAdminTemplateGenerate:
         })
         assert resp.status_code == 302
 
-        articles = await fetch_all("SELECT * FROM articles")
-        assert len(articles) == 3
-
-        scenarios = await fetch_all("SELECT * FROM published_scenarios")
-        assert len(scenarios) == 3
+        # Generation is now queued, not inline
+        tasks = await fetch_all(
+            "SELECT * FROM tasks WHERE task_name = 'generate_articles'"
+        )
+        assert len(tasks) == 1
+        import json
+        payload = json.loads(tasks[0]["payload"])
+        assert payload["template_slug"] == "test-city"
+        assert payload["start_date"] == "2026-04-01"
+        assert payload["articles_per_day"] == 2
 
     async def test_generate_unknown_template_redirects(self, admin_client, db, pseo_env):
         resp = await admin_client.get("/admin/templates/nonexistent/generate")
@@ -1042,13 +1047,7 @@ class TestAdminTemplateGenerate:
 
 
 class TestAdminTemplateRegenerate:
-    async def test_regenerate_updates_articles(self, admin_client, db, pseo_env):
-        from padelnomics.content import generate_articles
-        # First generate
-        await generate_articles("test-city", date(2026, 3, 1), 10)
-        initial = await fetch_all("SELECT * FROM articles")
-        assert len(initial) == 3
-
+    async def test_regenerate_enqueues_task(self, admin_client, db, pseo_env):
         async with admin_client.session_transaction() as sess:
             sess["csrf_token"] = "test"
 
@@ -1057,9 +1056,14 @@ class TestAdminTemplateRegenerate:
         })
         assert resp.status_code == 302
 
-        # Same count — upserted, not duplicated
-        articles = await fetch_all("SELECT * FROM articles")
-        assert len(articles) == 3
+        # Regeneration is now queued, not inline
+        tasks = await fetch_all(
+            "SELECT * FROM tasks WHERE task_name = 'generate_articles'"
+        )
+        assert len(tasks) == 1
+        import json
+        payload = json.loads(tasks[0]["payload"])
+        assert payload["template_slug"] == "test-city"
 
     async def test_regenerate_unknown_template_redirects(self, admin_client, db, pseo_env):
         async with admin_client.session_transaction() as sess: