Fix bugs found in local testing

- Dashboard auto-refresh rendered the full layout into its own
  refresh container, producing a duplicate sidebar every 60s; it now
  renders only the body partial.
- 'Run Now' runs synchronously with a bounded timeout and returns
  refreshed results plus success/error feedback, instead of
  firing-and-forgetting with no signal.
- Price-history chart data moved from a <script> block to a data-
  attribute: templ does not interpolate expressions inside <script>
  element content, so the JSON was emitted literally.
- The htmx indicator spinner was permanently visible due to CSS
  source order; the indicator rules now follow .v-spinner.

Also refreshes README for this session's changes.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

static/js/price-chart.js

@@ -0,0 +1,35 @@
+// Renders the price-history line chart on the per-item results page.
+// Chart data is read from the canvas's data-chart attribute: templ
+// interpolates attribute values but treats <script> element contents as raw
+// text, so the JSON cannot live in an inline <script> block. Loaded after
+// chart.umd.min.js with the #price-chart canvas already in the DOM above it.
+(function () {
+	var canvas = document.getElementById('price-chart');
+	if (!canvas || !canvas.dataset.chart || typeof Chart === 'undefined') {
+		return;
+	}
+	var data = JSON.parse(canvas.dataset.chart);
+	new Chart(canvas.getContext('2d'), {
+		type: 'line',
+		data: {
+			labels: data.labels,
+			datasets: [{
+				label: 'Best price',
+				data: data.points,
+				borderColor: '#00e4a4',
+				backgroundColor: 'rgba(0,228,164,0.15)',
+				pointBackgroundColor: '#e84040',
+				pointRadius: 3,
+				tension: 0.25,
+				fill: true
+			}]
+		},
+		options: {
+			scales: {
+				x: { ticks: { color: '#a8c0f0' }, grid: { color: 'rgba(255,255,255,0.07)' } },
+				y: { ticks: { color: '#a8c0f0' }, grid: { color: 'rgba(255,255,255,0.07)' } }
+			},
+			plugins: { legend: { labels: { color: '#ffffff' } } }
+		}
+	});
+})();