feat: update references section and fix experience logos in print

References section improvements:
- Remove TwenTIC recommendation letter
- Add Megabanner recommendations with author attribution (David Amorós)
- Update Presentation Letter URL to Domestika profile
- Update Chronological CV link to trigger PDF download modal
- Add 'action' field to Reference struct for custom behaviors

Print layout fixes:
- Show experience company logos in print view (40×40px)
- Remove print media query that was hiding .company-logo elements
- Maintain consistency with other logo types (courses, projects, awards)

Technical changes:
- Add Action field to Reference model with omitempty JSON tag
- Implement conditional rendering for downloadPDF action in template
- Links with action="downloadPDF" now call openPdfModal() function

data/cv-es.json

@@ -864,15 +864,16 @@
   ],
   "references": [
     {
-      "title": "Cartas de recomendación de TwenTiC",
-      "url": "http://www.drolosoft.com/2010/downloads/recomendacion.pdf",
+      "title": "Recomendaciones de Megabanner",
+      "url": "https://www.linkedin.com/in/juan-andres-moreno-rubio/details/recommendations/",
       "type": "recommendation",
-      "linkText": "Cartas de recomendación",
-      "textAfter": "de TwenTiC"
+      "textBefore": "Recomendaciones de",
+      "linkText": "Megabanner",
+      "textAfter": "(David Amorós)"
     },
     {
       "title": "Carta de presentación",
-      "url": "http://www.domestika.org/empleo/demanda/txeo",
+      "url": "https://www.domestika.org/es/txeo",
       "type": "presentation",
       "linkText": "Carta de presentación"
     },
@@ -906,8 +907,9 @@
     },
     {
       "title": "Currículum Vitae cronológico (7 páginas)",
-      "url": "javascript:window.print();document.getElementById('lengthToggle').checked=true;toggleCVLength();document.getElementById('themeToggle').checked=true;toggleTheme();setTimeout(()=>window.print(),100);",
+      "url": "#",
       "type": "cv",
+      "action": "downloadPDF",
       "textBefore": "Currículum Vitae",
       "linkText": "cronológico",
       "textAfter": "(7 páginas)"