fix(web): stop presenting an unscored case as a failed analysis, and four smaller things

From clicking through the redesigned UI:

- scoring a case without a model registry painted a red failure across a case that had in
  fact analysed fine. It is now a quiet note saying the model term contributes 0, because
  scoring is an optional fourth of the rank, not the analysis.
- the MLflow default moves to port 5001. On macOS, AirPlay Receiver owns 5000, which is why
  the registry answered "403" rather than refusing the connection; docker-compose publishes
  5001 to match.
- a funnel step that kept nothing drew a visible bar. Zero now draws zero.
- "1 candidates".
- the funnel's fixed grid columns forced a horizontal scrollbar on the report.

The report also lists the top undecided candidates now: the first thing anyone opens has no
decisions in it, and "Shortlisted (0)" alone said nothing about what the tool found.

Tests: api 77, web 32; ruff, mypy, svelte-check clean.

docker-compose.yml

@@ -42,7 +42,8 @@ services:
       mlflow server --host 0.0.0.0
       --backend-store-uri sqlite:////mlruns/mlflow.db
       --artifacts-destination /mlruns
-    ports: ["5000:5000"]
+    # 5001 on the host: macOS AirPlay Receiver owns 5000 and answers 403.
+    ports: ["5001:5000"]
     volumes: [mlruns:/mlruns]
 
 volumes: