feat: add SPH2025 video presentation page

- Create English-only page at /SPH2025 for job application video
- Embed video with HTML5 player and native browser controls
- Add URL aliases for /SPH2025/ and /sph2025/ accessibility
- Move video to static/videos/ directory for proper Hugo serving
- Responsive layout using Bootstrap grid

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

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

content/SPH2025/index.en.md

@@ -0,0 +1,11 @@
+---
+title: "SPH 2025 - Markus Graf"
+date: 2025-12-15
+description: "Video presentation for SPH 2025 job application"
+aliases: ["/SPH2025/", "/sph2025/"]
+---
+
+<video width="100%" controls>
+  <source src="/videos/20251214_FullStack_MarkusGraf.mp4" type="video/mp4">
+  Your browser does not support the video tag.
+</video>