docs: Rename PDF length parameter from 'detailed' to 'short'

Changed PDF export naming convention from 'detailed' to 'short' for better clarity and contrast with 'extended'. Updated:

- Documentation: All references from 'detailed' → 'short'
- JSON data files: Static PDF URLs now use cv-short-jamr-{{YEAR}}-{lang}.pdf
- Frontend modal: Removed 'short' → 'detailed' mapping (now stays as 'short')
- Static PDFs: Renamed cv-detailed-* to cv-short-* (deleted old files)
- Backend validation: Change

templates/partials/modals/pdf-modal.html

@@ -247,8 +247,8 @@
             console.log('Download requested for format:', selectedFormat);
 
             if (selectedFormat === 'short') {
-                // Short CV: clean version (no skills), detailed length
-                url = `/export/pdf?lang=${lang}&length=detailed&icons=show&version=clean`;
+                // Short CV: clean version (no skills), short length
+                url = `/export/pdf?lang=${lang}&length=short&icons=show&version=clean`;
             } else if (selectedFormat === 'long') {
                 // Long CV: with skills sidebar, extended length
                 url = `/export/pdf?lang=${lang}&length=extended&icons=show&version=with_skills`;
@@ -256,8 +256,8 @@
                 // Current view: use localStorage settings
                 let currentLength = localStorage.getItem('cv-length') || 'short';
                 // Map old values to new naming convention
-                if (currentLength === 'short') currentLength = 'detailed';
                 if (currentLength === 'long') currentLength = 'extended';
+                // 'short' stays as 'short' - no mapping needed
 
                 const currentIcons = localStorage.getItem('cv-icons') || 'show';
                 const currentTheme = localStorage.getItem('cv-theme') || 'default';