feat(web): self-service cheie/creds + admin web + email signup (PRD 3.3b)

US-007: rute web proprii /cont/roteste-cheie + /cont/rar-creds scoped pe
sesiune (C13), sectiune "Contul meu" cu cheie afisata o data.
US-010: rol admin (users.is_admin) + require_admin->403 + CLI set-admin +
bootstrap primul cont=admin (count_admins in BEGIN IMMEDIATE, anti-race).
US-011: panou /admin (activare/dezactivare conturi, CSRF + PRG), link admin
+ logout pe dashboard.
US-012: app/email.py notify_signup best-effort degradat fara SMTP + config smtp_*.
Fix: migrare defensiva users.is_admin/email_verified in _migrate.

VERIFY x2 context curat (PASS) + /code-review high. 393 teste pass.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

app/web/templates/dashboard.html

@@ -1,6 +1,15 @@
 {% extends "base.html" %}
 {% block content %}
 
+<!-- Nav cont: link admin (doar pentru admini) + logout -->
+<div style="display:flex; gap:8px; justify-content:flex-end; margin-bottom:12px; flex-wrap:wrap;">
+  {% if is_admin %}<a class="cardlink" href="/admin">Panou admin</a>{% endif %}
+  <form method="post" action="/logout" style="display:inline; margin:0;">
+    <input type="hidden" name="csrf_token" value="{{ csrf_token }}">
+    <button type="submit" style="background:var(--card); color:var(--muted); border-color:var(--line);">Iesi din cont</button>
+  </form>
+</div>
+
 <!-- Sectiunea de import fisier: stare initiala = drop zone; HTMX swapeaza in flow -->
 {% include '_upload.html' %}
 
@@ -32,6 +41,10 @@
   <div class="card"><div class="empty">se incarca mapari…</div></div>
 </div>
 
+<div hx-get="/_fragments/cont" hx-trigger="load" hx-swap="outerHTML">
+  <div class="card"><div class="empty">se incarca cont…</div></div>
+</div>
+
 <div class="card">
   <div style="display:flex; align-items:center; gap:8px; flex-wrap:wrap; margin:0 0 12px;">
     <h2 style="font-size:15px; margin:0;">Coada submissions</h2>