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

internal/models/cv.go

@@ -152,7 +152,8 @@ type Course struct {
 type Reference struct {
 	Title      string `json:"title"`
 	URL        string `json:"url"`
-	Type       string `json:"type"` // "recommendation", "portfolio", "profile", "cv", "presentation"
+	Type       string `json:"type"`                 // "recommendation", "portfolio", "profile", "cv", "presentation"
+	Action     string `json:"action,omitempty"`     // Optional action like "downloadPDF"
 	TextBefore string `json:"textBefore,omitempty"` // Text before the link
 	LinkText   string `json:"linkText,omitempty"`   // Bold text inside the link
 	TextAfter  string `json:"textAfter,omitempty"`  // Text after the link