feat(web): score an already-annotated case without re-running the pipeline

A case analysed before a model existed stayed unscored forever: the only control on the page
was "Re-analyse case", which re-runs five minutes of VEP to obtain a score that takes a second.
When any candidate is unscored the page now offers "Score variants" on its own.

Tests: web 34; svelte-check clean.

web/src/lib/candidates.test.ts

@@ -1,5 +1,5 @@
 import { describe, expect, it } from 'vitest';
-import { barWidth, candidateQuery, evidenceChips, funnelSteps, plural, scoreBarPercent } from './candidates';
+import { barWidth, candidateQuery, evidenceChips, funnelSteps, needsScoring, plural, scoreBarPercent } from './candidates';
 import type { Candidate, Funnel } from './api';
 
 const candidate = (over: Partial<Candidate> = {}): Candidate => ({
@@ -113,3 +113,14 @@ describe('plural', () => {
     expect(plural(12, 'candidate')).toBe('12 candidates');
   });
 });
+
+describe('needsScoring', () => {
+  it('spots candidates analysed before a model existed', () => {
+    expect(needsScoring([candidate({ scored: false })])).toBe(true);
+  });
+
+  it('is quiet once everything carries a score', () => {
+    expect(needsScoring([candidate({ scored: true })])).toBe(false);
+    expect(needsScoring([])).toBe(false);
+  });
+});

web/src/lib/candidates.ts

@@ -76,3 +76,6 @@ export function barWidth(value: number, total: number): number {
 }
 
 export const plural = (n: number, noun: string): string => `${n} ${noun}${n === 1 ? '' : 's'}`;
+
+/** True when a case was analysed before a model existed: scoring can be run on its own. */
+export const needsScoring = (items: Candidate[]): boolean => items.some((c) => !c.scored);

web/src/routes/cases/[id]/+page.svelte

@@ -3,7 +3,7 @@
   import { api, type Candidate, type CandidatePage, type Case, type Job, type VariantDetail } from '$lib/api';
   import { poll } from '$lib/poll';
   import { formatElapsed, latestStep } from '$lib/progress';
-  import { plural } from '$lib/candidates';
+  import { needsScoring, plural } from '$lib/candidates';
   import CandidateRow from '$lib/components/CandidateRow.svelte';
   import Funnel from '$lib/components/Funnel.svelte';
   import VariantPanel from '$lib/components/VariantPanel.svelte';
@@ -31,6 +31,9 @@
   const elapsedMs = $derived(job ? now - Date.parse(job.created_at) : 0);
   const step = $derived(scoring ? 'scoring variants with the model' : latestStep(job?.log ?? null));
   const termCount = $derived(kase?.phenotypes.length ?? 0);
+  // Annotation is expensive and scoring is not: a case annotated before a model existed should
+  // not need a five-minute re-run of VEP to get its score.
+  const unscored = $derived(!!page && page.items.length > 0 && needsScoring(page.items));
 
   // Tick the elapsed time while a run is in flight; polling refreshes the step itself.
   $effect(() => {
@@ -154,6 +157,9 @@
 {:else}
   <p class="actions">
     <button onclick={analyse} disabled={busy}>{job ? 'Re-analyse case' : 'Analyse case'}</button>
+    {#if unscored}
+      <button class="quiet" onclick={scoreThenLoad}>Score variants</button>
+    {/if}
     {#if page && page.funnel.total > 0}
       <a class="reportlink" href="/cases/{data.caseId}/report">Case report →</a>
     {/if}