Initial version of fail2ban-webui

Web interface to view, ban and unban fail2ban IPs on several hosts via
SSH, generalised from the private f2b-web tool.

- Web UI (Flask/Waitress): hosts.yaml, local/OIDC/proxy authentication,
  English/German UI, origin map, optional Loki/Grafana/GeoIP, CLI helpers
- Agent f2b-webctl with install.sh/uninstall.sh (dedicated user + sudo,
  from= restriction, protected networks, manual jail)
- Hardened Docker image, examples, documentation, smoke test, testbed

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

app/webui/templates/index.html

@@ -0,0 +1,79 @@
+{% extends "base.html" %}
+
+{% block header_meta %}
+    <span id="generated">–</span>
+    <button id="refresh" type="button">{{ t('refresh') }}</button>
+    {% if client_config.grafana and client_config.grafanaDashboard %}<a class="btn-link" href="{{ client_config.grafana }}{{ client_config.grafanaDashboard }}" target="_blank" rel="noopener">{{ t('grafana') }}</a>{% endif %}
+{% endblock %}
+
+{% block content %}
+<main>
+  <section id="hosts" class="cards"></section>
+
+  {% if geo_enabled %}
+  <section class="panel map-panel">
+    <div class="toolbar">
+      <h2>{{ t('map_heading') }}</h2>
+      <span id="map-summary" class="muted"></span>
+      <button id="map-reset" type="button" class="small" hidden>{{ t('map_reset') }}</button>
+    </div>
+    <div class="map">
+      <svg id="map" viewBox="0 5 360 145" role="img" aria-label="{{ t('map_heading') }}">
+        <image href="{{ url_for('static', filename='world.svg') }}" x="0" y="5" width="360" height="145"/>
+        <g id="map-points"></g>
+      </svg>
+    </div>
+    <p class="hint">{{ t('map_hint') }}</p>
+  </section>
+  {% endif %}
+
+  <section class="panel">
+    <h2>{{ t('ban_heading') }}</h2>
+    <form id="ban-form" autocomplete="off">
+      <input id="ban-ip" type="text" placeholder="{{ t('ban_ip_placeholder') }}" required>
+      <input id="ban-note" type="text" placeholder="{{ t('ban_note_placeholder') }}" maxlength="200">
+      <span class="hosts-select">
+        {% for h in hosts %}<label><input type="checkbox" name="ban-host" value="{{ h }}" checked> {{ h }}</label>{% endfor %}
+      </span>
+      <button type="submit" class="danger">{{ t('ban_button') }}</button>
+    </form>
+    <p class="hint">{{ t('ban_hint', jail=manual_jail) }}</p>
+  </section>
+
+  <section class="panel">
+    <div class="toolbar">
+      <h2>{{ t('bans_heading') }} <span id="count" class="badge">0</span></h2>
+      <input id="filter-text" type="search" placeholder="{{ t('filter_search') }}">
+      <select id="filter-host"><option value="">{{ t('filter_all_hosts') }}</option></select>
+      <select id="filter-jail"><option value="">{{ t('filter_all_jails') }}</option></select>
+    </div>
+    <div class="table-wrap">
+      <table>
+        <thead>
+          <tr><th>{{ t('col_host') }}</th><th>{{ t('col_jail') }}</th><th>{{ t('col_ip') }}</th><th>{{ t('col_origin') }}</th><th>{{ t('col_since') }}</th><th>{{ t('col_until') }}</th><th>{{ t('col_actions') }}</th></tr>
+        </thead>
+        <tbody id="bans"><tr><td colspan="7" class="muted">{{ t('loading') }}</td></tr></tbody>
+      </table>
+    </div>
+  </section>
+
+  <section class="panel">
+    <h2>{{ t('audit_heading') }}</h2>
+    <ul id="audit" class="audit"></ul>
+  </section>
+</main>
+
+<dialog id="history">
+  <div class="dialog-head">
+    <h2 id="history-title"></h2>
+    <button type="button" id="history-close" aria-label="{{ t('history_close') }}">✕</button>
+  </div>
+  <div id="history-body"></div>
+</dialog>
+
+<div id="toast" role="status" aria-live="polite"></div>
+<script id="i18n" type="application/json">{{ i18n | tojson }}</script>
+<script id="client-config" type="application/json">{{ client_config | tojson }}</script>
+{% endblock %}
+
+{% block scripts %}<script src="{{ url_for('static', filename='app.js') }}"></script>{% endblock %}