Fix: Add missing auth-params endpoint for login

functions/api/auth-params.js

@@ -0,0 +1,21 @@
+const json = (d, o) => new Response(JSON.stringify(d), { ...o, headers: { 'Content-Type': 'application/json' } });
+
+export async function onRequestGet({ request, env }) {
+  try {
+    const u = new URL(request.url).searchParams.get('username');
+    if (!u) return json({ error: 'Missing username' }, { status: 400 });
+
+    const pass_hash = await env.D1_SPCHCAP.prepare('SELECT pass_hash FROM users WHERE username = ?').bind(u).first('pass_hash');
+    if (!pass_hash) return json({ error: 'User not found' }, { status: 404 });
+    
+    const parts = pass_hash.split('$');
+    if (parts.length !== 6 || parts[0] !== 'scrypt') {
+      return json({ error: 'Invalid hash format' }, { status: 500 });
+    }
+    
+    const [_, N, r, p, salt_b64] = parts;
+    return json({ N: +N, r: +r, p: +p, salt_b64 });
+  } catch (e) {
+    return json({ error: { message: e.message } }, { status: 500 });
+  }
+}