style: apply ruff format and extend gitignore

Ruff auto-fixes import order and line wrapping. Gitignore covers
build artifacts and coverage output from future test runs.

Co-authored-by: Cursor <cursoragent@cursor.com>

app/main.py

@@ -92,9 +92,11 @@ def job_detail(request: Request, job_id: str) -> HTMLResponse:
     paths = pipeline.job_paths(stem)
     status = pipeline.read_status(stem) or {}
     manifest = pipeline.read_manifest(stem) or {"variants": []}
-    intermediates = sorted(
-        p.name for p in paths.intermediates.glob(f"{stem}_*.png") if p.is_file()
-    ) if paths.intermediates.exists() else []
+    intermediates = (
+        sorted(p.name for p in paths.intermediates.glob(f"{stem}_*.png") if p.is_file())
+        if paths.intermediates.exists()
+        else []
+    )
 
     return templates.TemplateResponse(
         "job.html",