Fix lint:diff-with-main oxlint rules build dependency (#20389)

## Summary

Closes #20382.

`lint:diff-with-main` can load `.oxlintrc.json` files that reference
`../twenty-oxlint-rules/dist/oxlint-plugin.mjs`, but the diff-lint
targets did not build `twenty-oxlint-rules` first. On fresh clones, that
generated plugin file is missing and oxlint fails before linting.

This PR adds `twenty-oxlint-rules:build` before diff lint for:
- the root `lint:diff-with-main` target default
- the custom `twenty-front:lint:diff-with-main` target
- the custom `twenty-server:lint:diff-with-main` target

It also adds regression coverage for:
- the default diff-lint target dependency
- the custom front/server diff-lint target dependencies
- preserving `twenty-website-new` custom dependencies because it does
not load the Twenty oxlint plugin

## Tests

- `npx vitest run --config
packages/twenty-oxlint-rules/vitest.config.mts
workspace/lint-diff-with-main-targets.spec.ts`
- `node_modules/.bin/nx test twenty-oxlint-rules`
- `node_modules/.bin/nx typecheck twenty-oxlint-rules`
- `node_modules/.bin/nx build twenty-oxlint-rules`
- `node_modules/.bin/nx lint:diff-with-main twenty-server`
- `node_modules/.bin/nx lint:diff-with-main twenty-front`
- `npx oxlint -c packages/twenty-oxlint-rules/.oxlintrc.json
packages/twenty-oxlint-rules/workspace/lint-diff-with-main-targets.spec.ts`
- `git diff --check`

## Notes

- `twenty-website-new:lint:diff-with-main` dependency shape remains
unchanged. Full local execution is blocked by missing local `unzip`,
which the existing `check-lottie-frames` script requires.

## Docs / Changelog

No docs or manual changelog update needed. This fixes Nx task wiring for
an existing documented command.

---------

Co-authored-by: Charles Bochet <charles@twenty.com>

nx.json

@@ -57,6 +57,7 @@
     "lint:diff-with-main": {
       "executor": "nx:run-commands",
       "cache": false,
+      "dependsOn": ["twenty-oxlint-rules:build"],
       "options": {
         "command": "FILES=$(git diff --name-only --diff-filter=d main -- {projectRoot}/ | grep -E '{args.pattern}'); [ -z \"$FILES\" ] && echo 'No changed files.' || (npx oxlint -c {projectRoot}/.oxlintrc.json $FILES && (prettier --check $FILES || (echo 'ERROR: Prettier formatting check failed! Fix with: npx nx lint:diff-with-main --configuration=fix' && false)))",
         "pattern": "\\.(ts|tsx|js|jsx)$"

packages/twenty-front/project.json

@@ -87,6 +87,7 @@
     },
     "lint:diff-with-main": {
       "executor": "nx:run-commands",
+      "dependsOn": ["twenty-oxlint-rules:build"],
       "options": {
         "cwd": "{projectRoot}",
         "command": "FILES=$(git diff --name-only --relative --diff-filter=d main...HEAD -- src/ | grep -E '\\.(ts|tsx)$'); [ -z \"$FILES\" ] && echo 'No changed files.' || (npx oxlint --type-aware -c .oxlintrc.json $FILES && (prettier --check $FILES || (echo 'ERROR: Prettier formatting check failed! Fix with: npx nx lint:diff-with-main twenty-front --configuration=fix' && false)))"

packages/twenty-server/project.json

@@ -169,6 +169,7 @@
     },
     "lint:diff-with-main": {
       "executor": "nx:run-commands",
+      "dependsOn": ["twenty-oxlint-rules:build"],
       "options": {
         "cwd": "{projectRoot}",
         "command": "FILES=$(git diff --name-only --relative --diff-filter=d main...HEAD -- src/ | grep -E '\\.(ts|tsx)$'); [ -z \"$FILES\" ] && echo 'No changed files.' || (npx oxlint --type-aware -c .oxlintrc.json $FILES && (prettier --check $FILES || (echo 'ERROR: Prettier formatting check failed! Fix with: npx nx lint:diff-with-main twenty-server --configuration=fix' && false)))"