feat: Implement Sprint 8 - Portfolio website expansion (MVP)

New pages:
- Home: Redesigned with hero, impact stats, featured project
- About: 6-section professional narrative
- Projects: Hub with 4 project cards and status badges
- Resume: Inline display with download placeholders
- Contact: Form UI (disabled) with contact info
- Blog: Markdown-based system with frontmatter support

Infrastructure:
- Blog system with markdown loader (python-frontmatter, markdown, pygments)
- Sidebar callback for active state highlighting on navigation
- Separated navigation into main pages and projects/dashboards groups

Closes #36, #37, #38, #39, #40, #41, #42, #43

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

pyproject.toml

@@ -48,6 +48,11 @@ dependencies = [
     # Utilities
     "python-dotenv>=1.0",
     "httpx>=0.28",
+
+    # Blog/Markdown
+    "python-frontmatter>=1.1",
+    "markdown>=3.5",
+    "pygments>=2.17",
 ]
 
 [project.optional-dependencies]
@@ -148,5 +153,7 @@ module = [
     "pdfplumber.*",
     "tabula.*",
     "pydantic_settings.*",
+    "frontmatter.*",
+    "markdown.*",
 ]
 ignore_missing_imports = true