refactor: Extract all hardcoded content to JSON files

- Move all bilingual text from templates to UI JSON (labels, buttons, modals)
- Move skills summary paragraph to CV JSON with HTML support
- Add new UI sections: navigation, viewControls, sections, footer, portfolio,
  pdfModal, shortcutsModal, infoModal, widgets
- Update Go structs to match expanded JSON structure
- Add template.HTML type for CV.SkillsSummary field
- Add JSON content validation test (70-json-content-validation.test.mjs)

Templates now contain only structural logic (CSS classes, HTML attributes)
while all user-visible text loads from JSON files for proper i18n support.

templates/partials/sections/projects.html

@@ -8,7 +8,7 @@
             <summary>
                 <h3 class="section-title">
                     <iconify-icon icon="mdi:web" width="24" height="24" class="section-icon"></iconify-icon>
-                    {{if eq .Lang "es"}}Proyectos Personales / Freelance{{else}}Personal / Freelance Projects{{end}}
+                    {{.UI.Navigation.Projects}}
                 </h3>
             </summary>
         {{range .CV.Projects}}
@@ -31,9 +31,9 @@
                 {{end}}
             </strong>
             {{if .Current}}<span class="live-badge"><iconify-icon icon="mdi:wifi" width="14" height="14"></iconify-icon>LIVE</span>{{end}}
-            {{if .MaintainedBy}}<span class="maintained-badge">{{if eq $.Lang "es"}}MANTENIDO POR{{else}}MAINTAINED BY{{end}} {{.MaintainedBy}}</span>{{end}}
+            {{if .MaintainedBy}}<span class="maintained-badge">{{$.UI.Sections.MaintainedBy}} {{.MaintainedBy}}</span>{{end}}
             <br>
-            <small>{{if .StartDate}}{{.StartDate}}{{if .Current}}{{if .DynamicDate}} / {{.DynamicDate}}{{else}} / {{if eq $.Lang "es"}}presente{{else}}ahora{{end}}{{end}}{{end}}{{end}} - ({{.Location}})</small>
+            <small>{{if .StartDate}}{{.StartDate}}{{if .Current}}{{if .DynamicDate}} / {{.DynamicDate}}{{else}} / {{$.UI.Sections.Present}}{{end}}{{end}}{{end}} - ({{.Location}})</small>
 
             {{if .ShortDescription}}
             <p class="project-desc short-desc">{{.ShortDescription | safeHTML}}</p>
@@ -49,7 +49,7 @@
 
             {{if .Technologies}}
             <div class="project-technologies long-only">
-                <strong>{{if eq $.Lang "es"}}Tecnologías:{{else}}Technologies:{{end}}</strong>
+                <strong>{{$.UI.Sections.Technologies}}</strong>
                 {{range $index, $tech := .Technologies}}{{if $index}}, {{end}}{{$tech}}{{end}}
             </div>
             {{end}}
@@ -59,8 +59,8 @@
 
         <!-- Link to full portfolio -->
         <div class="projects-footer">
-            <p>{{if eq .Lang "es"}}Ver todos los proyectos en mi{{else}}See all projects on my{{end}}
-            <a href="{{.CV.Personal.Domestika}}" target="_blank" rel="noopener noreferrer"><strong>{{if eq .Lang "es"}}portfolio de Domestika{{else}}Domestika portfolio{{end}}</strong></a></p>
+            <p>{{.UI.Portfolio.SeeAllProjects}}
+            <a href="{{.CV.Personal.Domestika}}" target="_blank" rel="noopener noreferrer"><strong>{{.UI.Portfolio.DomestikaPortfolio}}</strong></a></p>
         </div>
         </details>
     </div>