Fix 5 bugs: analytics range keys, stale visitor rows, NuggetsPage init state, episodes timer leak, unsanitized nuggets object; v2.0.1

- analytics: union byDayReal+byDayBot keys so bot-only days aren't dropped from range totals
- analytics: exclude timestamp-less visitor rows from range filters (was unconditionally including them)
- App.tsx: init `configured` to false so a network failure doesn't show a misleading "no episodes" state; add r.ok guard before r.json()
- episodes.js: wrap fetch in try/catch so clearTimeout is called on network failure, matching the nuggets.js pattern
- helpers.js: add sanitizeNuggets + wire it into sanitizeSiteContent so corrupted hosts/urls can't crash NuggetsPage

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

src/App.tsx

@@ -1885,11 +1885,11 @@ function NuggetsPage({ content }: { content: SiteContent }) {
 
   const [episodes, setEpisodes] = useState<NuggetsEpisode[]>([])
   const [loading, setLoading] = useState(true)
-  const [configured, setConfigured] = useState(true)
+  const [configured, setConfigured] = useState(false)
 
   useEffect(() => {
     fetch('/api/nuggets/episodes/all')
-      .then(r => r.json())
+      .then(r => r.ok ? r.json() : Promise.reject(r.status))
       .then((d: { episodes?: NuggetsEpisode[]; configured?: boolean }) => {
         setEpisodes(Array.isArray(d.episodes) ? d.episodes : [])
         setConfigured(d.configured !== false)