Add Plausible analytics with JSON Upload custom event.

Load tagged-events from plausible.elpatron.me on all pages, allow it in CSP, and track successful save uploads with import status.

Co-authored-by: Cursor <cursoragent@cursor.com>

templates/_analytics.html

@@ -0,0 +1 @@
+<script defer data-domain="if-viewer.elpatron.me" src="https://plausible.elpatron.me/js/script.tagged-events.js"></script>

templates/index.html

@@ -5,6 +5,7 @@
   <meta name="viewport" content="width=device-width, initial-scale=1.0">
   <title>Idle Fantasy Viewer</title>
   <link rel="stylesheet" href="/static/style.css">
+  {% include '_analytics.html' %}
   <script src="/static/vendor/chart.umd.min.js" defer></script>
   <script src="/static/i18n.js" defer></script>
   <script src="/static/app.js" defer></script>

templates/landing.html

@@ -5,6 +5,7 @@
   <meta name="viewport" content="width=device-width, initial-scale=1.0">
   <title>Idle Fantasy Viewer</title>
   <link rel="stylesheet" href="/static/style.css">
+  {% include '_analytics.html' %}
   <script src="/static/i18n.js" defer></script>
   <script src="/static/landing.js" defer></script>
 </head>