feat: implement Watchtower theme for web UI

Replace Pico CSS with custom Watchtower theme (Sci-Fi Dark Mode):
- Add backend/static/ directory with Watchtower CSS files
- tokens_watchtower.css: Design tokens (colors, typography, spacing)
- theme_watchtower.css: Theme overrides for components

Features:
- High-contrast dark mode (#0b0f14 background)
- Neon accent color (#00e08f teal/cyan)
- Glow effects on buttons and inputs
- Radial gradient background
- SVG noise texture overlay (bg-noise class)
- Pill-shaped buttons (border-radius: 999px)
- Uppercase labels with letter-spacing
- Monospace font for logs

UI Enhancements:
- FastAPI static files mount added
- Custom styling for all components (sections, buttons, inputs, forms)
- Accent border-left on header and update status
- Improved visual hierarchy with color coding
- OIDC button gets secondary style (outline)

Complete US_000024 and TASK_000024.
Based on minecraft-watchtower UI design.
All Pico CSS dependencies removed.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

backend/static/theme_watchtower.css

@@ -0,0 +1,135 @@
+/*
+ wlkns-dev-standards
+ Component Theme: Watchtower
+ Adapts standard components to the Sci-Fi/Dark aesthetic.
+*/
+
+/* =========================
+   Inputs & Forms
+   ========================= */
+input, select, textarea {
+  background: rgba(10, 14, 20, 0.6) !important;
+  border-color: rgba(255, 255, 255, 0.15) !important;
+  color: var(--color-text) !important;
+  transition: all 0.2s ease;
+}
+
+input:focus, select:focus, textarea:focus {
+  border-color: var(--color-accent) !important;
+  box-shadow: 0 0 15px var(--wt-glow);
+}
+
+/* =========================
+   Buttons
+   ========================= */
+.button {
+  text-transform: uppercase;
+  letter-spacing: 0.05em;
+  font-weight: 600;
+  border-radius: 999px !important; /* Pill shape */
+}
+
+.button.primary {
+  box-shadow: 0 0 15px var(--wt-glow);
+  color: #081015; /* Dark text on bright accent */
+}
+
+.button.secondary {
+  background: transparent;
+  border: 1px solid rgba(255, 255, 255, 0.2);
+  color: var(--color-text);
+}
+
+.button.secondary:hover {
+  border-color: var(--color-text);
+  background: rgba(255,255,255,0.05);
+}
+
+.button.danger {
+  box-shadow: 0 0 10px rgba(255, 94, 94, 0.4);
+  color: #1b0d0d;
+}
+
+/* =========================
+   Tables
+   ========================= */
+table {
+  border-collapse: separate;
+  border-spacing: 0 4px; /* Space between rows */
+}
+
+thead th {
+  border-bottom: 1px solid var(--color-accent);
+  text-transform: uppercase;
+  letter-spacing: 0.1em;
+  font-size: 0.75rem;
+  color: var(--color-accent);
+  background: transparent;
+}
+
+tbody tr {
+  background: rgba(255, 255, 255, 0.03);
+  transition: transform 0.2s;
+}
+
+tbody tr:hover {
+  background: rgba(255, 255, 255, 0.06);
+  transform: scale(1.01);
+}
+
+tbody td {
+  border: none;
+}
+
+tbody td:first-child {
+  border-top-left-radius: 8px;
+  border-bottom-left-radius: 8px;
+}
+
+tbody td:last-child {
+  border-top-right-radius: 8px;
+  border-bottom-right-radius: 8px;
+}
+
+/* =========================
+   Alerts & Toasts
+   ========================= */
+.alert, .toast {
+  background: rgba(10, 14, 20, 0.95);
+  backdrop-filter: blur(4px);
+  border: 1px solid rgba(255, 255, 255, 0.1);
+  box-shadow: 0 10px 30px rgba(0,0,0,0.5);
+}
+
+.alert.success, .toast.success {
+  border-color: var(--color-success);
+  box-shadow: 0 0 10px rgba(0, 224, 143, 0.2);
+  color: var(--color-text);
+}
+
+.alert.warning, .toast.warning {
+  border-color: var(--color-warning);
+  color: var(--color-text);
+}
+
+.alert.error, .toast.error {
+  border-color: var(--color-error);
+  box-shadow: 0 0 10px rgba(255, 94, 94, 0.2);
+  color: var(--color-text);
+}
+
+/* =========================
+   Pagination
+   ========================= */
+.pagination .page {
+  background: transparent;
+  border: 1px solid rgba(255,255,255,0.1);
+  color: var(--color-text-muted);
+}
+
+.pagination .page.active {
+  background: var(--color-accent);
+  color: #081015;
+  border-color: var(--color-accent);
+  box-shadow: 0 0 10px var(--wt-glow);
+}