[codex] Clamp loaded item dimensions to limits

[nexiumbiz-debug]

Summary

• clamp loaded gridster item cols/
  ows against item-level or grid-level min/max limits before collision handling
• update the caller's item config when clamping changes dimensions
• emit itemChange for loaded items whose dimensions are normalized

Fixes #284.

Validation

• npm run test-lib -- --watch=false
• npm run build-lib
• npx eslint projects/angular-gridster2/src/lib/tests/gridster.spec.ts
• npx eslint projects/angular-gridster2/src/lib/gridster.ts projects/angular-gridster2/src/lib/tests/gridster.spec.ts (blocked by pre-existing upstream gridster.ts lint errors: component selector, prefer-for-of, no-inferrable-types, unused eslint-disable)
• git diff --check