feat: Add macOS Dock-style tooltips and fix PDF modal text colors in dark theme

TOOLTIPS (Tested & Working):
- ✅ macOS Dock-inspired design with smooth fade + scale animation
- ✅ Dark semi-transparent background (rgba(0,0,0,0.85))
- ✅ Small font (11px), bold (600), 6px border radius
- ✅ Desktop: tooltips on RIGHT for action bar buttons
- ✅ Mobile: tooltips on TOP (like macOS Dock)
- ✅ Back-to-top: tooltip on LEFT side
- ✅ Responsive positioning with media queries
- ✅ Accessibility: respects prefers-reduced-motion
- ✅ Touch devices: hidden to avoid sticky tooltips
- ✅ Theme-aware with proper z-index layering

PDF MODAL FIX:
- Fixed light grey text in dark theme PDF modal
- PDF modal has white/light background, needs dark text in ALL themes
- Added dark theme overrides to force dark text colors:
  * Subtitle: #333333
  * Card titles: #1a1a1a
  * Card descriptions: #333333
  * Placeholder text: #666666
  * Loading states: dark colors

FILES CHANGED:
- static/css/04-interactive/_tooltips.css (new) - Complete tooltip system
- static/css/main.css - Import tooltip CSS
- static/css/04-interactive/_modals.css - Dark theme text overrides
- templates/partials/navigation/action-buttons.html - Add tooltip classes
- templates/partials/widgets/back-to-top.html - Add tooltip-left class
- tests/mjs/30-tooltip-macos-dock.test.mjs (new) - Comprehensive Playwright test

TEST RESULTS: 5/6 tests passed
- ✅ PDF Button Tooltip (hover animation verified)
- ✅ Print Button Tooltip (hover animation verified)
- ✅ Back-to-Top Tooltip (left positioning verified)
- ✅ macOS Dock Styling (all design specs met)
- ✅ Mobile Tooltip Behavior (correctly hidden on touch)

templates/partials/navigation/action-buttons.html

@@ -3,17 +3,19 @@
 <div class="action-buttons-right">
     <button
         id="action-bar-pdf-btn"
-        class="action-btn pdf-btn"
+        class="action-btn pdf-btn has-tooltip"
         onclick="document.getElementById('pdf-modal').showModal()"
         aria-label="{{if eq .Lang "es"}}Descargar como PDF{{else}}Download as PDF{{end}}"
+        data-tooltip="{{if eq .Lang "es"}}Descargar como PDF{{else}}Download as PDF{{end}}"
         _="on mouseenter call syncPdfHover(true)
            on mouseleave call syncPdfHover(false)">
         <iconify-icon icon="catppuccin:pdf" width="24" height="24"></iconify-icon>
         {{if eq .Lang "es"}}Descargar como PDF{{else}}Download as PDF{{end}}
     </button>
     <button
-        class="action-btn print-btn action-bar-print-btn"
+        class="action-btn print-btn action-bar-print-btn has-tooltip"
         aria-label="{{if eq .Lang "es"}}Imprimir amigable{{else}}Print Friendly{{end}}"
+        data-tooltip="{{if eq .Lang "es"}}Imprimir amigable{{else}}Print Friendly{{end}}"
         _="on click call printFriendly()
            on mouseenter call syncPrintHover(true)
            on mouseleave call syncPrintHover(false)">