Add hide component feature, usage indicators, and Docker support

- Add is_hidden field to hide components from configurator
- Add colored dot indicator showing component usage status:
  - Green: available in configurator
  - Cyan: used as source for meta-articles
  - Gray: hidden from configurator
- Optimize price recalculation with caching and skip unchanged
- Show current lot name during price recalculation
- Add Dockerfile (Alpine-based multi-stage build)
- Add docker-compose.yml and .dockerignore

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

migrations/003_add_is_hidden.sql

@@ -0,0 +1,2 @@
+-- Add is_hidden column to qt_lot_metadata table
+ALTER TABLE qt_lot_metadata ADD COLUMN is_hidden BOOLEAN DEFAULT FALSE COMMENT 'Hide component from configurator';