feat: add curriculum vitae page with secure download

Add dedicated CV page for HR professionals and recruiters with secure Tresorit download link.

Changes:
- Add CV content page at /cv/ with German text
- Configure CV navigation menu item "Curriculum Vitae"
- Enhance navigation template with active state handling for menu items
- Add secure external link with target="_blank" and security attributes (noopener, noreferrer, nofollow)
- Include email verification notice and information about certificates/references availability
- Create OpenSpec proposal for content-management capability

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

openspec/changes/add-cv-page/tasks.md

@@ -0,0 +1,27 @@
+## 1. Content Creation
+- [x] 1.1 Create `content/cv.md` with German CV page content
+- [x] 1.2 Add front matter with title "Lebenslauf" and appropriate metadata
+- [x] 1.3 Write clear instructions for Tresorit download process
+- [x] 1.4 Include secure download link (https://web.tresorit.com/l/khkGf#UBmRnKs_3dkUTZRwtbbdUQ)
+- [x] 1.5 Mention email verification requirement
+- [x] 1.6 Explain that certificates and references are available on personal request
+
+## 2. Navigation Configuration
+- [x] 2.1 Update `hugo.toml` to add CV page to main menu
+- [x] 2.2 Configure menu item with German label "Lebenslauf"
+- [x] 2.3 Set appropriate menu weight for ordering
+- [x] 2.4 Verify menu link points to `/cv/`
+
+## 3. Navigation Template Enhancement
+- [x] 3.1 Review `layouts/partials/nav.html` for active state handling
+- [x] 3.2 Ensure CV link shows active state when on CV page
+- [x] 3.3 Test navigation styling consistency
+
+## 4. Testing & Validation
+- [x] 4.1 Test CV page renders correctly in development mode
+- [x] 4.2 Verify navigation link appears and points to correct URL
+- [x] 4.3 Test active state styling on CV page
+- [x] 4.4 Verify Tresorit link is clickable and correct
+- [x] 4.5 Check responsive layout on mobile devices (tested via generated HTML - Bootstrap responsive classes in place)
+- [x] 4.6 Validate German language and professional tone
+- [x] 4.7 Test production build