Initial vibeproxy implementation

Self-contained HTTP/HTTPS/TCP/UDP reverse proxy manager written in Go,
with SQLite storage, a Bootstrap 5 admin UI (Go templates, no JS
framework), and a REST API under /api/v1.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01QTXFrNP1imCW7jtfL5SZrw

internal/web/templates/backends.html

@@ -0,0 +1,24 @@
+{{define "backends"}}{{template "header" .}}
+<p class="text-secondary">Live backend status from the running configuration. Add or edit backends from the owning Proxy Host.</p>
+<div class="card">
+  <div class="table-responsive">
+    <table class="table table-hover align-middle mb-0" id="backendsListTable">
+      <thead class="table-light"><tr><th>Proxy Host</th><th>Backend</th><th>Weight</th><th>Health Check</th><th>Config</th><th>Live Health</th></tr></thead>
+      <tbody>
+      {{range .Data}}
+        <tr>
+          <td><a href="/proxy-hosts/{{.ProxyHostID}}/edit">{{.ProxyHostName}}</a></td>
+          <td>{{.Host}}:{{.Port}}</td>
+          <td>{{.Weight}}</td>
+          <td>{{.HealthCheck}}</td>
+          <td>{{if .Enabled}}<span class="badge text-bg-success">enabled</span>{{else}}<span class="badge text-bg-secondary">disabled</span>{{end}}</td>
+          <td>{{if .Healthy}}<span class="badge text-bg-success"><i class="bi bi-heart-pulse"></i> healthy</span>{{else}}<span class="badge text-bg-danger"><i class="bi bi-heart-pulse"></i> unhealthy</span>{{end}}</td>
+        </tr>
+      {{else}}
+        <tr><td colspan="6" class="text-center text-secondary py-4">No backends configured.</td></tr>
+      {{end}}
+      </tbody>
+    </table>
+  </div>
+</div>
+{{template "footer" .}}{{end}}