feat: portage complet en Rust (axum + sysinfo + tera)

Remplacement du backend Python/Flask par un binaire Rust natif.
Stack : axum (web), sysinfo (metriques), lettre (SMTP), tera (templates), argon2 (auth).
Binaire Windows 6.3 Mo sans dependance runtime.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

templates/alerts.html

@@ -1,11 +1,11 @@
 {% extends "base.html" %}
-{% block title %}Supervision - Alertes{% endblock %}
+{% block title %}Supervision - Alertes{% endblock title %}
 
 {% block content %}
 <div class="d-flex justify-content-between align-items-center mb-3">
     <h4 class="mb-0"><i class="bi bi-bell"></i> Historique des alertes</h4>
     {% if alerts %}
-    <form method="POST" action="{{ url_for('clear_alerts') }}">
+    <form method="POST" action="/alerts/clear">
         <button type="submit" class="btn btn-sm btn-outline-danger"
                 onclick="return confirm('Effacer tout l\'historique ?')">
             <i class="bi bi-trash"></i> Effacer l'historique
@@ -35,10 +35,10 @@
                 {% for alert in alerts %}
                 <tr>
                     <td class="text-nowrap">
-                        <small>{{ alert.timestamp[:19] | replace('T', ' ') }}</small>
+                        <small>{{ alert.timestamp | truncate(length=19, end="") | replace(from="T", to=" ") }}</small>
                     </td>
                     <td>
-                        {% if alert.type == 'process_down' %}
+                        {% if alert.type == "process_down" %}
                         <span class="badge bg-danger">Processus</span>
                         {% else %}
                         <span class="badge bg-warning text-dark">Seuil</span>
@@ -57,4 +57,4 @@
     {{ alerts | length }} alerte(s) — les 500 dernieres sont conservees.
 </div>
 {% endif %}
-{% endblock %}
+{% endblock content %}