feat: Add CMD+K command palette with ninja-keys integration

Implement a command palette accessible via CMD+K/Ctrl+K using the ninja-keys
web component. Features include:

- New /api/cmd-k endpoint serving dynamic CV entries (experiences, projects, courses)
- Language-aware responses with 1-hour cache headers
- Scroll-to-section functionality for quick navigation
- Enhanced keyboard shortcuts modal with CMD+K documentation
- Comprehensive test coverage for API and UI interactions

Also includes cleanup of deprecated debug test files and various UI polish
improvements to contact form, themes, and action bar components.

static/css/04-interactive/_contact-form.css

@@ -2,6 +2,11 @@
    CONTACT FORM - Modal form styling
    ============================================================================= */
 
+/* Utility class to hide elements after form submission */
+.hidden {
+    display: none !important;
+}
+
 /* Contact Modal Specific Overrides */
 #contact-modal {
     max-width: 520px;
@@ -256,10 +261,10 @@
    CONTACT BUTTON (Fixed Position)
    ============================================================================= */
 
-/* Contact Button - positioned above bottom buttons */
-.contact-btn {
-    position: fixed;
-    bottom: 14rem; /* Above zoom button */
+/* Contact Button - positioned above theme switcher (FIXED sidebar button only) */
+.fixed-btn.contact-btn {
+    position: fixed !important; /* Override .has-tooltip position: relative */
+    bottom: 18rem; /* Above theme switcher (14rem) */
     left: 2rem;
     width: 50px;
     height: 50px;
@@ -277,16 +282,16 @@
     opacity: 0.6;
 }
 
-.contact-btn:hover {
+.fixed-btn.contact-btn:hover {
     opacity: 1;
     transform: translateY(-3px);
     box-shadow: 0 6px 16px rgba(0, 0, 0, 0.4);
     background: #3498db; /* Blue hover */
 }
 
-.contact-btn.at-bottom {
+.fixed-btn.contact-btn.at-bottom {
     opacity: 1;
-    background: #3498db; /* Blue when at bottom */
+    background: #3498db !important; /* Blue when at bottom */
 }
 
 /* =============================================================================
@@ -343,8 +348,8 @@
         font-size: 0.75rem;
     }
 
-    /* Contact button mobile */
-    .contact-btn {
+    /* Contact button mobile (FIXED sidebar button only) */
+    .fixed-btn.contact-btn {
         bottom: 13.5rem; /* Adjust for mobile button spacing */
         left: 1.5rem;
         width: 45px;