feat: initial Speedboard implementation

sitespeed.io web UI with Express/Pug/SQLite — port 3132.
Includes job queue, SSE live log, full metrics dashboard,
site history, CO2/axe/CWV sections, and Docker support.

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

views/partials/scorecard.pug

@@ -0,0 +1,12 @@
+- function scoreColor(s) { return s == null ? '#9ca3af' : s >= 90 ? '#22c55e' : s >= 50 ? '#f59e0b' : '#ef4444'; }
+- function scoreBg(s) { return s == null ? 'bg-gray-100 text-gray-400' : s >= 90 ? 'bg-green-100 text-green-700' : s >= 50 ? 'bg-yellow-100 text-yellow-700' : 'bg-red-100 text-red-700'; }
+- const scores = [['Overall', job.score_overall], ['Performance', job.score_performance], ['Accessibility', job.score_accessibility], ['Best Practice', job.score_bestpractice], ['Privacy', job.score_privacy]]
+
+div(class='bg-white border border-gray-200 rounded-xl p-5')
+  h2(class='text-base font-semibold mb-4') Coach Scores
+  div(class='flex flex-wrap gap-4 justify-start')
+    each item in scores
+      div(class='flex flex-col items-center gap-1')
+        div(class=`score-circle w-16 h-16 text-xl ${scoreBg(item[1])}`)
+          = item[1] != null ? Math.round(item[1]) : '?'
+        span(class='text-xs text-gray-500 text-center')= item[0]