Read-time: full-article "Full story · ~N min" badge (Option B)

Replaces the gist-based read-time with the SOURCE article's full read time — the
contrast that sells the gist ("calm 1-min version here; ~10 min for the deep dive").

- goodnews/readtime.py: word_count_from_html (strips script/style/nav/header/
  footer/form/button/aside furniture before counting) + source_read_minutes
  (~225 wpm, 200-word floor, None when extraction looks failed/too thin).
- articles.source_words + read_checked_at columns (count only, never the body;
  fits the privacy posture). Idempotent migration.
- enrich.fetch_source_words + enrich_read_times: a bounded, retry-guarded cycle
  step (mirrors the image enrichers) that counts words for recent accepted
  articles. Only ever writes a real count; never overwrites good with zero. Wired
  into the cycle after recent-image enrichment.
- queries: source_words flows through _ARTICLE_COLUMNS; api exposes
  source_read_minutes on Article (null when unknown).
- home3: News card shows "Full story · ~N min", hidden entirely when null (no
  misleading "1 min").
- Tests: furniture stripping, threshold/rounding, enrich idempotency + no
  zero-overwrite, API null handling. 412 backend.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

frontend/src/routes/home3/+page.svelte

@@ -26,10 +26,10 @@
   // truncation handled by CSS (-webkit-line-clamp:2) — breaks on whole words, fills 2 full lines
   let headline = $derived(news?.title ?? 'What went right this week: the good news that actually matters');
 
-  // Honest read-time from our own gist (~200 wpm, floor 1). We summarize, so this is
-  // usually "1 min read" — a feature, not a bug: the good news in about a minute.
-  const readMins = (t) => Math.max(1, Math.round((t || '').trim().split(/\s+/).filter(Boolean).length / 200));
-  let readTime = $derived(`${readMins(news?.summary)} min read`);
+  // The badge shows how long the FULL source article takes — the contrast that sells
+  // the gist ("the calm 1-min version here; ~10 min if you want the deep dive"). Computed
+  // server-side from the source word count; hidden entirely when we couldn't measure it.
+  let fullRead = $derived(news?.source_read_minutes ? `Full story · ~${news.source_read_minutes} min` : '');
 
   // small-joys shelf: 3 cells shown two at a time, rotated by the reader (no auto-motion)
   const JOY_ACCENTS = ['#4f7da8', '#b06a86', '#b06a45'];
@@ -130,7 +130,7 @@
           <p class="summary">{news?.summary || "We read the week so you don't have to doomscroll it. Five quietly hopeful stories, summarised to the gist."}</p>
         </a>
         <div class="news-foot">
-          <span class="meta">{readTime}</span>
+          {#if fullRead}<span class="meta">{fullRead}</span>{/if}
         </div>
         <hr class="news-div" />
         <a class="news-more" href="/">Read more good news →</a>