Don't warn about Angular's ::ng-deep when optimizing generated CSS - #20437

Summary

Fixes #20433.

optimizeCss filters Lightning CSS warnings for the framework-specific deep selectors Vue emits (:deep(), :slotted(), :global()), but Angular's ::ng-deep isn't covered by that filter, so every Angular stylesheet using it prints a warning during optimization:

Issue #1:
│ :host ::ng-deep .some-child, :host
┆        ^-- 'ng-deep' is not recognized as a valid pseudo-element. Did you mean ':ng-deep' (pseudo-class) or is this a typo?

The existing regex (/'(deep|slotted|global)' is not recognized as a valid pseudo-/) requires a ' immediately before deep, but Lightning CSS's message quotes the full token 'ng-deep', so the character before deep is -, not ', and the filter never matches.

::ng-deep is Angular's supported deep-selector spelling (aliased to >>>//deep/, which are already silently accepted via nonStandard.deepSelectorCombinator), and it's the spelling used in Angular's own docs, so it's hit by essentially every Angular codebase that uses view-encapsulation-piercing styles.

Changes

• packages/@tailwindcss-node/src/optimize.ts: add ng-deep to the warning-suppression regex.
• packages/@tailwindcss-node/src/optimize.test.ts (new): covers that ::ng-deep no longer warns, that the existing :deep()/:slotted()/:global() suppression still works, and that a genuinely unrecognized pseudo-element still warns (so the filter isn't overly broad).
• CHANGELOG.md: added an entry under Unreleased > Fixed.

Test plan

• Added packages/@tailwindcss-node/src/optimize.test.ts and ran it with vitest run packages/@tailwindcss-node/src/optimize.test.ts— all 3 pass.
• Verified the new test fails on the pre-fix code (only the ::ng-deep case fails) by temporarily reverting the regex change and re-running.
• Ran the full @tailwindcss/node package test suite (vitest run --project @tailwindcss/node) — all 10 tests pass, no regressions.
• pnpm run lint (prettier check) passes on the changed files.