refactor: consolidate color definitions into single source of truth

- Create frontend/colors.mjs as SSOT for all design colors
- Create scripts/generate-css-vars.mjs to auto-generate CSS variables
- Update tailwind.config.ts to import colors from colors.mjs
- Update frontend/package.json: add 'generate-css-vars' script to build pipeline
- Update start_servers.py: include CSS variable generation before npm build
- All color changes now require only one edit in colors.mjs
- Build process auto-syncs CSS variables and Tailwind colors

Eliminates DRY violation where colors were duplicated in:
  - tailwind.config.ts (Tailwind utility classes)
  - globals.css (CSS custom properties)

Single source of truth approach ensures:
  ✓ No inconsistency between Tailwind and CSS variables
  ✓ One place to update colors for all contexts
  ✓ Automated CSS variable generation on every build

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

.claude/settings.local.json

@@ -148,7 +148,8 @@
       "Bash(/data/programare_AI/tfm_ainventory/.venv/bin/python3 *)",
       "Bash(curl -k -s -X POST https://192.168.84.131:8918/users/login -H 'Content-Type: application/json' -d '{\\\\\"username\\\\\":\\\\\"admin\\\\\",\\\\\"password\\\\\":\\\\\"admin\\\\\"}')",
       "Bash(curl -k -s -H \"Authorization: Bearer $\\(curl -k -s -X POST https://192.168.84.131:8918/users/login -H 'Content-Type: application/json' -d '{\\\\\"username\\\\\":\\\\\"admin\\\\\",\\\\\"password\\\\\":\\\\\"admin\\\\\"}')",
-      "Bash(curl -k -s https://192.168.84.131:8918/admin/db/export)"
+      "Bash(curl -k -s https://192.168.84.131:8918/admin/db/export)",
+      "Bash(node scripts/generate-css-vars.mjs)"
     ]
   }
 }