feat: integrate all 10 skills into homelab-topology

- Added api-security-hardening (helmet, rate limits)
- Added nodejs-backend-patterns (error handling)
- Added observability-monitoring (pino logging)
- Added websocket-engineer (socket.io real-time updates)
- Added docker (Multi-stage build, compose)
- Added vitest (testing configuration and store tests)
- Added data-visualizer (MetricsBar and HostChart)
- Added infrastructure-monitoring/proxmox-admin/network-engineer types
- Fixed UI accessibility and styling
- Cleaned up node_modules tracking

src/index.css

@@ -29,8 +29,58 @@ body {
   height: 100vh;
 }
 
+/* ── Skip link (a11y) ────────────────────────────────────── */
+.skip-link {
+  position: absolute;
+  top: -40px;
+  left: 0;
+  background: var(--accent);
+  color: #000;
+  padding: 8px 16px;
+  z-index: 100;
+  font-weight: 600;
+  transition: top 200ms ease-out;
+}
+
+.skip-link:focus {
+  top: 0;
+}
+
+/* ── Focus-visible styles (a11y) ─────────────────────────── */
+:focus {
+  outline: none;
+}
+
+:focus-visible {
+  outline: 2px solid var(--accent);
+  outline-offset: 2px;
+}
+
+button:focus-visible {
+  box-shadow: 0 0 0 3px rgba(56, 189, 248, 0.4);
+  outline: none;
+}
+
+/* ── Reduced motion (a11y) ───────────────────────────────── */
+@media (prefers-reduced-motion: reduce) {
+  *,
+  *::before,
+  *::after {
+    animation-duration: 0.01ms !important;
+    animation-iteration-count: 1 !important;
+    transition-duration: 0.01ms !important;
+    scroll-behavior: auto !important;
+  }
+
+  .react-flow__node {
+    transition: none !important;
+  }
+}
+
+/* ── React Flow overrides ────────────────────────────────── */
 .react-flow__node {
   cursor: pointer;
+  transition: transform 300ms ease-out;
 }
 
 .react-flow__edge-path {
@@ -66,3 +116,16 @@ body {
 .react-flow__controls-button svg {
   fill: currentColor;
 }
+
+/* ── Visually hidden utility (a11y) ──────────────────────── */
+.visually-hidden {
+  position: absolute;
+  width: 1px;
+  height: 1px;
+  padding: 0;
+  margin: -1px;
+  overflow: hidden;
+  clip: rect(0, 0, 0, 0);
+  white-space: nowrap;
+  border: 0;
+}