Replace Bootstrap with Tailwind CSS + Alpine.js (#14)

## Summary

Replaces Bootstrap CSS/JS framework with Tailwind CSS v4 + Alpine.js, matching the µPaaS UI pattern.

## Changes

- **Removed Bootstrap** — all Bootstrap CSS/JS references removed from templates
- **Added Tailwind CSS v4** — `static/css/input.css` with Material Design inspired theme, compiled to `static/css/tailwind.css`
- **Added Alpine.js 3.14.9** — vendored as `static/js/alpine.min.js` for reactive UI components
- **Rewrote all templates** to use Tailwind utility classes:
  - `base.html` — new layout structure with footer, matches µPaaS pattern
  - `htmlheader.html` — Tailwind CSS link, `[x-cloak]` style
  - `navbar.html` — Alpine.js mobile menu toggle, responsive design
  - `index.html` — card-based dashboard with Tailwind classes
  - `login.html` — centered login form with Material Design styling
  - `profile.html` — clean profile layout
- **Added `make css` target** — compiles Tailwind CSS using standalone CLI
- **Component classes** in `input.css` — reusable `.btn-primary`, `.card`, `.input`, `.alert-error` etc.

## Testing

- `make fmt` ✅
- `make check` (fmt-check, lint, test, build) ✅
- `docker build .` ✅

closes #4

Co-authored-by: user <user@Mac.lan guest wan>
Reviewed-on: #14
Co-authored-by: clawbot <clawbot@noreply.example.org>
Co-committed-by: clawbot <clawbot@noreply.example.org>

static/css/style.css

@@ -1,59 +1 @@
-/* Webhooker main stylesheet */
-body {
-    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
-} 
-
-/* Custom styles for Webhooker */
-
-/* Navbar customization */
-.navbar-brand {
-    font-weight: 600;
-    font-size: 1.5rem;
-}
-
-/* Card hover effects */
-.card {
-    transition: transform 0.2s ease-in-out, box-shadow 0.2s ease-in-out;
-}
-
-.card:hover {
-    transform: translateY(-5px);
-    box-shadow: 0 10px 30px rgba(0,0,0,0.15) !important;
-}
-
-/* Background opacity utilities */
-.bg-opacity-10 {
-    background-color: rgba(var(--bs-success-rgb), 0.1);
-}
-
-.bg-primary.bg-opacity-10 {
-    background-color: rgba(var(--bs-primary-rgb), 0.1);
-}
-
-/* User dropdown styling */
-.navbar .dropdown-toggle::after {
-    margin-left: 0.5rem;
-}
-
-.navbar .dropdown-menu {
-    margin-top: 0.5rem;
-}
-
-/* Footer styling */
-footer {
-    margin-top: auto;
-    padding: 2rem 0;
-    background-color: #f8f9fa;
-    border-top: 1px solid #dee2e6;
-}
-
-/* Responsive adjustments */
-@media (max-width: 768px) {
-    .display-4 {
-        font-size: 2.5rem;
-    }
-    
-    .card {
-        margin-bottom: 1rem;
-    }
-} 
+/* Webhooker custom styles — see input.css for Tailwind theme */