refactor: Major hyperscript refactoring and JS elimination

Inline Hyperscript Refactoring:
- Body tag keyboard handlers: 20→8 lines (using helper functions)
- Zoom control handlers: 85→35 lines (using zoom._hs)
- PDF modal card selection: 90→6 lines (3 identical blocks eliminated)

New Hyperscript Files:
- zoom._hs: handleZoomInput, handleZoomReset, initZoomControl
- pdf-modal._hs: selectPdfCard, handlePdfCardKey

JavaScript Elimination (232 lines removed):
- cv-functions.js: REMOVED - hyperscript defs are globally available
- scroll-at-bottom-handler.js: REMOVED - duplicate of handleScroll()
- footer-buttons-interaction.js: REMOVED - moved to hyperscript

Added Tests:
- 32-hyperscript-multi-src.test.mjs: Verifies multi-file loading
- 33-keyboard-shortcuts-refactored.test.mjs: Keyboard shortcuts
- 34-hyperscript-refactor-comprehensive.test.mjs: Full test suite

Key Findings:
- No hyperscript multi-file bug in 0.9.14
- Hyperscript def statements are globally accessible
- Previous refactoring failures were syntax errors, not library bugs

static/hyperscript/pdf-modal._hs

@@ -0,0 +1,45 @@
+-- File: pdf-modal._hs
+-- Purpose: PDF modal helper functions
+-- Last Updated: 2025-11-30
+
+-- ==============================================================================
+-- PDF CARD SELECTION HANDLER
+-- ==============================================================================
+-- Handles selection of PDF format cards in the modal
+-- Called from each card's click event
+def selectPdfCard(card)
+  -- Get the modal container
+  set modal to document.getElementById('pdf-modal')
+  if modal is null then exit end
+
+  -- Remove selected from all cards
+  set cards to modal.querySelectorAll('.pdf-option-card')
+  for c in cards
+    remove .selected from c
+    set c's @aria-checked to 'false'
+  end
+
+  -- Add selected to this card
+  add .selected to card
+  set card's @aria-checked to 'true'
+
+  -- Enable download button
+  set downloadBtn to modal.querySelector('.pdf-download-btn')
+  if downloadBtn is not null
+    remove @disabled from downloadBtn
+  end
+
+  -- Store selected format for download
+  set window.selectedPdfFormat to card's @data-cv-format
+end
+
+-- ==============================================================================
+-- PDF CARD KEYDOWN HANDLER
+-- ==============================================================================
+-- Handles keyboard navigation for PDF cards (Enter/Space to select)
+def handlePdfCardKey(card, evt)
+  if evt.key is 'Enter' or evt.key is ' '
+    call evt.preventDefault()
+    call selectPdfCard(card)
+  end
+end