Add Stripe donation flow

web/donation-complete.html

@@ -0,0 +1,19 @@
+<!doctype html>
+<html lang="en">
+<head>
+  <meta charset="utf-8">
+  <meta name="viewport" content="width=device-width,initial-scale=1">
+  <title>Contribution received | MedMind</title>
+  <style>
+    @font-face{font-family:Inter;src:url('/medmind-inter.ttf') format('truetype');font-display:swap}
+    :root{color-scheme:dark light;--bg:#071224;--surface:#0b1427;--border:#33415d;--text:#f8fafc;--muted:#a9b5ca;--accent:#38bdf8;--success:#22c55e}
+    @media(prefers-color-scheme:light){:root{--bg:#f1f5f9;--surface:#fff;--border:#dbe3ef;--text:#0f172a;--muted:#64748b}}
+    :root[data-theme=light]{--bg:#f1f5f9;--surface:#fff;--border:#dbe3ef;--text:#0f172a;--muted:#64748b}
+    *{box-sizing:border-box}body{margin:0;min-height:100vh;display:grid;place-items:center;padding:24px;background:var(--bg);color:var(--text);font-family:Inter,system-ui,sans-serif}
+    main{width:min(560px,100%);padding:40px;border:1px solid var(--border);border-radius:12px;background:var(--surface);text-align:center}
+    img{width:84px;height:84px;object-fit:contain}h1{margin:22px 0 12px;font-size:30px}p{margin:0;color:var(--muted);font-size:17px;line-height:1.6}.status{color:var(--success);font-weight:700}
+  </style>
+</head>
+<script>try{document.documentElement.dataset.theme=localStorage.getItem('medmind-color-scheme')||''}catch(e){}</script>
+<body><main><img src="/medmind-loader-icon.png" alt="MedMind"><h1>Thank you for supporting MedMind</h1><p class="status">Your checkout is complete.</p><p>You can close this tab and return to MedMind. Stripe will send your receipt by email.</p></main></body>
+</html>