feat: per-project portal password gate (/portal/p/{token}) + lockout

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

templates/portal/password.html

@@ -0,0 +1,26 @@
+{% extends "portal/base.html" %}
+{% block title %}{{ project_name }}{% endblock %}
+{% block content %}
+<div class="max-w-md mx-auto mt-20 text-center reveal">
+    <div class="panel inline-flex items-center justify-center w-16 h-16 rounded-2xl mb-6">
+        <svg class="w-7 h-7 text-[var(--text-dim)]" fill="none" stroke="currentColor" viewBox="0 0 24 24">
+            <path stroke-linecap="round" stroke-linejoin="round" stroke-width="1.5"
+                  d="M12 15v2m-6 4h12a2 2 0 002-2v-6a2 2 0 00-2-2H6a2 2 0 00-2 2v6a2 2 0 002 2zm10-10V7a4 4 0 00-8 0v4h8z"></path>
+        </svg>
+    </div>
+    <h1 class="text-2xl font-bold tracking-tight mb-1">{{ project_name }}</h1>
+    <p class="text-[var(--text-dim)] text-sm mb-6">Enter the password to view this monitoring portal.</p>
+    {% if error %}
+    <p class="text-[var(--lvl-bad)] text-sm mb-4">{{ error }}</p>
+    {% endif %}
+    <form method="post" action="/portal/p/{{ link_token }}" class="panel p-5 text-left">
+        <label class="block text-xs text-[var(--text-dim)] mb-1" for="password">Password</label>
+        <input id="password" name="password" type="password" autofocus required
+               class="w-full px-3 py-2 rounded-lg border border-[var(--border)] bg-[var(--panel-b)] text-[var(--text)] mb-4">
+        <button type="submit"
+                class="w-full px-4 py-2 rounded-lg bg-seismo-orange text-white font-medium hover:opacity-90">
+            View portal
+        </button>
+    </form>
+</div>
+{% endblock %}