feat: enhance CV with project title links, experience durations, certifications, and improved navigation

## Project Title Links
- Add projectName and projectDesc fields to Project struct
- Split project titles to make only project name clickable
- Update template logic for conditional title rendering
- Apply changes to both English and Spanish versions

## Experience Duration Display
- Restore duration calculation display in experience section
- Move duration from date line to after company name
- Style duration in light gray (#999) for subtle appearance
- Calculate durations dynamically (e.g., "4 years 10 months")

## Certifications Section Enhancement
- Add Codecademy Certifications (2022-2024) with AI Transformers and React courses
- Add LinkedIn Learning Certifications (2019-2020) with 5 professional courses
- Implement colored icon system with brand colors (purple, cyan, green, etc.)
- Use responsibilities format matching Third Party Contributions layout
- Reorder courses chronologically (most recent first)

## localStorage Improvements
- Save CV length preference (short/long)
- Save logos visibility preference (show/hide)
- Save theme preference (default/clean)
- Restore all preferences on page load

## Navigation UX Enhancements
- Fix scroll positioning to show sections below action bar
- Add keepHeaderVisible flag to maintain header visibility after navigation
- Ensure smooth scrolling with proper offset calculations
- Reset flag on scroll up to restore normal hide/show behavior

## Files Modified
- internal/models/cv.go: Add ProjectName, ProjectDesc fields
- templates/cv-content.html: Update project and experience rendering
- static/css/main.css: Add duration-text styling
- templates/index.html: Enhance scroll behavior and localStorage
- data/cv-*.json: Add certifications, split project titles, reorder courses
- static/images/courses/: Add codecademy.png, linkedin.png

internal/models/cv.go

@@ -101,13 +101,15 @@ type Language struct {
 
 type Project struct {
 	Title            string   `json:"title"`
+	ProjectName      string   `json:"projectName,omitempty"`      // Optional: linkable part of title
+	ProjectDesc      string   `json:"projectDesc,omitempty"`      // Optional: non-linkable description part
 	URL              string   `json:"url"`
-	ProjectLogo      string   `json:"projectLogo,omitempty"`  // Optional logo filename
-	GitRepoUrl       string   `json:"gitRepoUrl,omitempty"`    // Optional git repository URL for dynamic dates
+	ProjectLogo      string   `json:"projectLogo,omitempty"`      // Optional logo filename
+	GitRepoUrl       string   `json:"gitRepoUrl,omitempty"`       // Optional git repository URL for dynamic dates
 	Location         string   `json:"location"`
-	StartDate        string   `json:"startDate,omitempty"`     // Optional static start date
+	StartDate        string   `json:"startDate,omitempty"`        // Optional static start date
 	Current          bool     `json:"current"`
-	MaintainedBy     string   `json:"maintainedBy,omitempty"` // Optional maintainer name (e.g., "SAP")
+	MaintainedBy     string   `json:"maintainedBy,omitempty"`     // Optional maintainer name (e.g., "SAP")
 	Technologies     []string `json:"technologies"`
 	ShortDescription string   `json:"shortDescription"`
 	Responsibilities []string `json:"responsibilities"`