feat(nx): add lint and test targets to all projects (M5)

[Chloe_he (Chloe-He)]

• Add @nx/eslint plugin to nx.json for lint target inference
• Add lint and test targets to all 92 project.json files
• Configure caching for lint, test, and typecheck targets
• Enable per-project task execution via Nx

This enables:

• nx lint <project> - Run ESLint on specific project
• nx test <project> - Run Jest on specific project
• nx run-many --target=lint - Run lint on all projects
• nx affected --target=test - Run tests on changed projects only
• Computation caching - Skip unchanged work

Note: CI workflow updates deferred to future PR.
Note: typecheck target deferred due to project-level tsconfig complexity.

Remember to include the following changes:

• Ensure the PR title includes the name of the component you are changing so it's clear in the release notes for consumers of the changes in the version e.g [Clover-123][BpkButton] Updating the colour
• README.md (If you have created a new component)
• Component README.md
• Tests
• Accessibility tests
  • The following checks were performed:
    • Ability to navigate using a keyboard only
    • Zoom functionality (Deque University explanation):
      • The page SHOULD be functional AND readable when only the text is magnified to 200% of its initial size
      • Pages must reflow as zoom increases up to 400% so that content continues to be presented in only one column i.e. Content MUST NOT require scrolling in two directions (both vertically and horizontally)
    • Ability to navigate using a screen reader only
• Storybook examples created/updated
• For breaking changes or deprecating components/properties, migration guides added to the description of the PR. If the guide has large changes, consider creating a new Markdown page inside the component's docs folder and link it here