feat: add capacity planning docs, image upload system, and platform health monitoring

Documentation:
- Add comprehensive capacity planning guide (docs/architecture/capacity-planning.md)
- Add operations docs: platform-health, capacity-monitoring, image-storage
- Link pricing strategy to capacity planning documentation
- Update mkdocs.yml with new Operations section

Image Upload System:
- Add ImageService with WebP conversion and sharded directory structure
- Generate multiple size variants (original, 800px, 200px)
- Add storage stats endpoint for monitoring
- Add Pillow dependency for image processing

Platform Health Monitoring:
- Add /admin/platform-health page with real-time metrics
- Show CPU, memory, disk usage with progress bars
- Display capacity thresholds with status indicators
- Generate scaling recommendations automatically
- Determine infrastructure tier based on usage
- Add psutil dependency for system metrics

Admin UI:
- Add Capacity Monitor to Platform Health section in sidebar
- Create platform-health.html template with stats cards
- Create platform-health.js for Alpine.js state management

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

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

mkdocs.yml

@@ -41,6 +41,7 @@ nav:
     - Frontend Structure: architecture/frontend-structure.md
     - Models Structure: architecture/models-structure.md
     - Background Tasks: architecture/background-tasks.md
+    - Capacity Planning: architecture/capacity-planning.md
     - API Consolidation:
       - Proposal: architecture/api-consolidation-proposal.md
       - Migration Status: architecture/api-migration-status.md
@@ -186,6 +187,14 @@ nav:
     - Environment Variables: deployment/environment.md
     - Stripe Integration: deployment/stripe-integration.md
 
+  # ============================================
+  # OPERATIONS (Platform Health & Monitoring)
+  # ============================================
+  - Operations:
+    - Platform Health: operations/platform-health.md
+    - Capacity Monitoring: operations/capacity-monitoring.md
+    - Image Storage: operations/image-storage.md
+
   # ============================================
   # FEATURES
   # ============================================