Add Plausible custom events + weekly insights dashboard + cron

- Custom Plausible events: Pricing Click, Chat Toggle, Chat Message Sent,
  FAQ Toggle, Speedrun Nav, Mobile Menu Toggle, Scroll Depth (25/50/75/100%)
- Weekly Insights section on launch dashboard with visitor/pageview/bounce
  rate/visit duration/top pages/top referrers + analysis cards
- data/insights.json for storing weekly analytics summaries
- scripts/check-plausible-email.py — finds latest Plausible email via IMAP
- Cron job: every Mon 09:00 PYST, reads Plausible email, writes insights,
  analyzes and implements improvements

data/insights.json

@@ -0,0 +1,18 @@
+{
+  "week": "—",
+  "updated": "—",
+  "visitors": 0,
+  "visitors_change": "",
+  "pageviews": 0,
+  "pageviews_change": "",
+  "bounce_rate": "—",
+  "bounce_rate_change": "",
+  "visit_duration": "—",
+  "visit_duration_change": "",
+  "top_pages": [],
+  "top_referrers": [],
+  "events": [],
+  "what_worked": [],
+  "what_didnt": [],
+  "recommendations": []
+}