Move tools/eslint-rules to packages/twenty-eslint-rules (#17203)

## Summary

Moves the custom ESLint rules from `tools/eslint-rules` to
`packages/twenty-eslint-rules` for better organization within the
monorepo packages structure.

## Changes

- Move `eslint-rules` from `tools/` to `packages/twenty-eslint-rules`
- Use `loadWorkspaceRules` from `@nx/eslint-plugin` to load custom rules
- Update all ESLint configs to use the `twenty/` rule prefix instead of
`@nx/workspace-`
- Update `project.json`, `jest.config.mjs` with new paths
- Update `package.json` workspaces and `nx.json` cache inputs
- Update Dockerfile reference

## Technical Details

The custom ESLint rules are now loaded using Nx's `loadWorkspaceRules`
utility which:
- Handles TypeScript transpilation automatically
- Allows loading workspace rules from any directory
- Provides a cleaner approach than the previous `@nx/workspace-`
convention

## Testing

- Verified all 17 custom ESLint rules load correctly from the new
location
- Verified linting works on dependent packages (twenty-front,
twenty-server, etc.)

packages/twenty-docker/twenty-website/Dockerfile

@@ -8,7 +8,7 @@ COPY ./yarn.lock .
 COPY ./.yarnrc.yml .
 COPY ./.yarn/releases /app/.yarn/releases
 COPY ./.yarn/patches /app/.yarn/patches
-COPY ./tools/eslint-rules /app/tools/eslint-rules
+COPY ./packages/twenty-eslint-rules /app/packages/twenty-eslint-rules
 COPY ./packages/twenty-ui/package.json /app/packages/twenty-ui/
 COPY ./packages/twenty-shared/package.json /app/packages/twenty-shared/
 COPY ./packages/twenty-website/package.json /app/packages/twenty-website/package.json