feat: add zoom control with accessibility and persistence

UI Components:
- Fixed bottom-center zoom slider (50%-200% range, step 5%)
- Modern glass-morphism design with gradient slider track
- Reset button with smooth rotation animation
- Real-time zoom percentage display
- Fully responsive (desktop/tablet/mobile)

Functionality:
- CSS transform-based zoom (GPU accelerated)
- localStorage persistence across sessions
- Keyboard shortcuts: Ctrl/Cmd +/-/0
- Smooth transitions with debouncing (50ms)
- Scroll position preservation during zoom
- Print mode: Temporarily resets to 100%

Accessibility (WCAG AA):
- Complete ARIA labels and live regions
- Keyboard navigation support
- Focus indicators on all interactive elements
- Screen reader compatible (announces zoom level)
- Touch-friendly (44px+ targets)

Integration:
- Follows existing toggle patterns (length, logos, theme)
- Initializes in initPreferences()
- Works with print-friendly mode
- Hidden in print (.no-print class)
- Bilingual support (English/Spanish)

Performance:
- will-change: transform for compositor layer
- Debounced slider input for smooth dragging
- requestAnimationFrame for scroll preservation
- No layout thrashing (transform-only changes)

Technical Details:
- Range: 50-200 (prevents unusability, allows 2x mag)
- Transform origin: top center (maintains alignment)
- Transition: 300ms cubic-bezier (material design)
- Storage key: 'cv-zoom'
- Default: 100% (normal view)

static/js/main.js

@@ -254,6 +254,136 @@
         }
     };
 
+    // =============================================================================
+    // ZOOM CONTROL
+    // =============================================================================
+
+    /**
+     * Initialize zoom control on page load
+     * Restores saved zoom level from localStorage
+     */
+    function initZoomControl() {
+        const slider = document.getElementById('zoom-slider');
+        const resetBtn = document.getElementById('zoom-reset');
+        const cvPaper = document.querySelector('.cv-paper');
+
+        if (!slider || !cvPaper) return;
+
+        // Restore saved zoom level
+        const savedZoom = localStorage.getItem('cv-zoom');
+        if (savedZoom) {
+            const zoomValue = parseInt(savedZoom, 10);
+            slider.value = zoomValue;
+            applyZoom(zoomValue, false); // false = don't save (already loaded from storage)
+        }
+
+        // Real-time slider updates with debouncing for performance
+        let zoomTimeout;
+        slider.addEventListener('input', function(e) {
+            const zoomValue = parseInt(e.target.value, 10);
+
+            // Update ARIA and display immediately (no debounce)
+            updateZoomDisplay(zoomValue);
+
+            // Debounce the actual transform application (smoother on slower devices)
+            clearTimeout(zoomTimeout);
+            zoomTimeout = setTimeout(() => {
+                applyZoom(zoomValue, true);
+            }, 50); // 50ms debounce
+        });
+
+        // Reset button
+        if (resetBtn) {
+            resetBtn.addEventListener('click', function() {
+                slider.value = 100;
+                applyZoom(100, true);
+                slider.focus(); // Return focus to slider for accessibility
+            });
+        }
+
+        // Keyboard shortcuts (Ctrl/Cmd + Plus/Minus/0)
+        document.addEventListener('keydown', function(e) {
+            if ((e.ctrlKey || e.metaKey) && !e.shiftKey) {
+                if (e.key === '=' || e.key === '+') {
+                    e.preventDefault();
+                    incrementZoom(5);
+                } else if (e.key === '-') {
+                    e.preventDefault();
+                    incrementZoom(-5);
+                } else if (e.key === '0') {
+                    e.preventDefault();
+                    slider.value = 100;
+                    applyZoom(100, true);
+                }
+            }
+        });
+    }
+
+    /**
+     * Apply zoom transformation to CV paper
+     * @param {number} zoomValue - Zoom percentage (50-200)
+     * @param {boolean} saveToStorage - Whether to persist to localStorage
+     */
+    function applyZoom(zoomValue, saveToStorage = true) {
+        const cvPaper = document.querySelector('.cv-paper');
+        if (!cvPaper) return;
+
+        // Convert percentage to scale factor (100 = 1.0, 150 = 1.5, etc.)
+        const scaleFactor = zoomValue / 100;
+
+        // Preserve scroll position (matching existing toggle pattern)
+        requestAnimationFrame(() => {
+            const scrollTop = window.pageYOffset || document.documentElement.scrollTop;
+
+            // Apply transform
+            cvPaper.style.transform = `scale(${scaleFactor})`;
+
+            // Restore scroll position
+            window.scrollTo(0, scrollTop);
+
+            // Update display
+            updateZoomDisplay(zoomValue);
+
+            // Save to localStorage
+            if (saveToStorage) {
+                localStorage.setItem('cv-zoom', zoomValue.toString());
+            }
+        });
+    }
+
+    /**
+     * Update visual display and ARIA attributes
+     * @param {number} zoomValue - Current zoom percentage
+     */
+    function updateZoomDisplay(zoomValue) {
+        const slider = document.getElementById('zoom-slider');
+        const display = document.getElementById('zoom-display');
+
+        if (display) {
+            display.textContent = `${zoomValue}%`;
+        }
+
+        if (slider) {
+            slider.setAttribute('aria-valuenow', zoomValue);
+            slider.setAttribute('aria-valuetext', `${zoomValue}%`);
+        }
+    }
+
+    /**
+     * Increment/decrement zoom by step amount
+     * @param {number} step - Amount to change (positive or negative)
+     */
+    function incrementZoom(step) {
+        const slider = document.getElementById('zoom-slider');
+        if (!slider) return;
+
+        const currentZoom = parseInt(slider.value, 10);
+        const newZoom = Math.min(200, Math.max(50, currentZoom + step));
+
+        slider.value = newZoom;
+        applyZoom(newZoom, true);
+    }
+
     // =============================================================================
     // PRINT & PDF
     // =============================================================================
@@ -265,6 +395,9 @@
         const wasClean = container.classList.contains('theme-clean');
         const wasLong = paper.classList.contains('cv-long');
 
+        // Store current zoom
+        const currentZoom = localStorage.getItem('cv-zoom') || '100';
+
         // Apply clean theme for minimal print (no sidebars, no header, no icons)
         if (!wasClean) {
             container.classList.add('theme-clean');
@@ -274,6 +407,11 @@
         paper.classList.remove('cv-long');
         paper.classList.add('cv-short');
 
+        // Temporarily reset zoom for printing
+        if (paper) {
+            paper.style.transform = 'scale(1)';
+        }
+
         // Small delay to let CSS apply
         setTimeout(() => {
             window.print();
@@ -288,6 +426,10 @@
                     paper.classList.remove('cv-short');
                     paper.classList.add('cv-long');
                 }
+                // Restore zoom
+                if (paper && currentZoom !== '100') {
+                    applyZoom(parseInt(currentZoom, 10), false);
+                }
             }, 100);
         }, 50);
     };
@@ -354,6 +496,9 @@
         if (themeChecked) {
             window.toggleTheme();
         }
+
+        // Initialize zoom control
+        initZoomControl();
     }
 
     // =============================================================================