feat: add progress page with activity calendar, book grid, and insights

Adds a new /progress route showing a personalized Bible knowledge dashboard
with stat cards, book mastery grid, 30-day activity calendar, skill growth
chart, streak milestones, and section insights. Links added from WinScreen
(logged-in users) and DevButtons.

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

src/lib/components/DevButtons.svelte

@@ -69,6 +69,12 @@
 	>
 		📊 View Stats
 	</a>
+	<a
+		href="/progress"
+		class="inline-flex items-center justify-center w-full px-4 py-4 md:py-2 bg-emerald-600 text-white rounded-lg hover:bg-emerald-700 transition-colors text-sm font-medium shadow-md"
+	>
+		📈 View Progress
+	</a>
 
 	{#if user}
 		<form method="POST" action="/auth/logout" use:enhance class="w-full">