Drop title/intro, freeze through last Friday midday, render dates in UTC

- Remove the visible title and challenge-explanation paragraph so the plot
embeds cleanly in a blog that already describes the challenge.
- Freeze data through Fri 2026-06-19 16:00 UTC (UNTIL cutoff), excluding the
late-Friday submissions that were only verified afterward — so the SOTA is
byteshark (491.8 TPS), the top verified result as of the snapshot.
- Render all dates (header, axis, hover card) in UTC so the frozen plot reads
identically regardless of the viewer's timezone.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

README.md

@@ -49,4 +49,14 @@ rewrites the embedded `<script id="snapshot">` block in place:
 node build_snapshot.mjs
 ```
 
+The freeze window is controlled by the `UNTIL` cutoff in `build_snapshot.mjs` (currently
+`2026-06-19T16:00:00Z` — last Friday midday UTC). It excludes the late-Friday submissions that
+were only verified afterward, so the plotted SOTA reflects what was verified as of the snapshot.
+Override per-run with an env var — a date (`UNTIL=2026-06-19`, treated as end-of-day UTC), a full
+ISO timestamp, or `UNTIL=` (empty) to include everything:
+
+```bash
+UNTIL=2026-06-19T16:00:00Z node build_snapshot.mjs
+```
+
 Override the source with `API_BASE=… node build_snapshot.mjs` if the dashboard ever moves.

build_snapshot.mjs

@@ -20,6 +20,15 @@ const HTML_PATH = join(HERE, 'index.html');
 // each replaces ~680 individual bucket fetches.
 const API_BASE = process.env.API_BASE || 'https://gemma-challenge-gemma-dashboard.hf.space';
 
+// Freeze window: include only submissions up to and including this UTC instant.
+// Set to last Friday midday for the current snapshot — this excludes the late
+// Friday-evening submissions that were only verified afterward, so the SOTA
+// reflects what was verified as of the snapshot (byteshark, 491.8 TPS).
+// Override with UNTIL=YYYY-MM-DD or a full ISO timestamp; UNTIL= (empty) keeps
+// everything. A date with no time is treated as end-of-day UTC.
+const UNTIL = process.env.UNTIL ?? '2026-06-19T16:00:00Z';
+const CUTOFF_MS = UNTIL ? Date.parse(/T/.test(UNTIL) ? UNTIL : `${UNTIL}T23:59:59.999Z`) : Infinity;
+
 const BUCKET_WEB_URL = 'https://huggingface.co/buckets/gemma-challenge/gemma-main-bucket';
 const TPS_MIN = 0, TPS_MAX = 1_000_000;
 const FILENAME_RE = /^(\d{8})-(\d{6})(?:-\d{3})?_(.+?)(?:_(.+))?\.md$/;
@@ -135,6 +144,7 @@ async function getJson(url) {
 
 async function main() {
   console.log(`Fetching snapshot from ${API_BASE} …`);
+  console.log(`Including submissions ${UNTIL ? `through ${UNTIL} (UTC)` : '(no cutoff)'}`);
   const [resultsRes, agentsRes, verifyMap] = await Promise.all([
     getJson(`${API_BASE}/api/results`),
     getJson(`${API_BASE}/api/agents`),
@@ -145,6 +155,7 @@ async function main() {
   const entries = (resultsRes.items || [])
     .map(it => parseResultFile(it.filename, it.content))
     .filter(Boolean)
+    .filter(e => (Date.parse(e.date) || 0) <= CUTOFF_MS)
     .map(e => ({ ...e, verification: verificationState(e.filename) }));
 
   const agents = {};