Unblock tailwindcss past 4.3.0 (4.3.1+ scans the git-ignored `.web` tree)

[masenf]

TailwindV4Plugin is pinned at tailwindcss@4.3.0 / @tailwindcss/postcss@4.3.0, held there by the note on Constants.VERSION in packages/reflex-base/src/reflex_base/plugins/tailwind_v4.py:

Held at 4.3.0: 4.3.1+ reworked source-file scanning (tailwindlabs/tailwindcss#20214, #20217, #20203) and walks the git-ignored .web tree, which collapses the docs prod build at scale.

I checked whether 4.3.2 or 4.3.3 lifted the hold while refreshing dependencies in #7019, and they don't:

• 4.3.1 — #20214 "Ensure explicitly referenced @source directories are scanned even when ignored by git". This is the change that causes our problem, and it is deliberate upstream behavior, not a bug they intend to revert.
• 4.3.2 — #20246 (CLI --watch rebuild in an ignored dir), #20263 ("Prevent @source patterns from scanning unrelated sibling files and folders"). Adjacent, but does not restore the pre-4.3.1 gitignore behavior.
• 4.3.3 — #20335 (@source ordering with nested vs. parent folders), #20336 (Vite full-reload avoidance). Also unrelated to the gitignore walk.

So the pin cannot move on a version bump alone — the fix has to be on our side, in what we hand Tailwind as sources. tailwindcss and @tailwindcss/postcss are now filtered out of the outdated-dependency check with a pointer here, so they will stop showing up as perpetually-stale rows until this is resolved.

Why our config trips it

TailwindV4Plugin writes tailwind.config.js inside .web and pulls it in from the root stylesheet with @config "../tailwind.config.js". The default content globs (Constants.CONTENT) are .web-relative:

./app/**/*.{js,ts,jsx,tsx}
./utils/**/*.{js,ts,jsx,tsx}

Because .web is git-ignored, pre-4.3.1 Tailwind skipped it; from 4.3.1 an explicitly referenced directory is scanned regardless, so the scan now also reaches build output under .web (build/, node_modules/, .react-router/) at docs scale.

What needs doing

• Reproduce at docs scale — a small app builds fine on 4.3.3 (verified in Refresh outdated dependencies flagged on the release branch #7019), so this needs the real docs/app prod build to show the collapse
• Narrow what Tailwind is given: tighten the content globs, and/or add @source not exclusions for .web/build, .web/node_modules, and .web/.react-router
• Confirm a docs prod build on 4.3.3 with the corrected sources completes in a comparable time to 4.3.0
• Bump Constants.VERSION and the @tailwindcss/postcss pin, and drop the note that pins them
• Remove \| tailwindcss and \| @tailwindcss/postcss from the frontend ignore list in .github/workflows/check_outdated_dependencies.yml

Notes

@tailwindcss/typography (0.5.20) and the docs app's tailwindcss-animated / tailwindcss-scroll-mask are unaffected and stay in the outdated check — the ignore patterns are anchored on the table's package column specifically so they are not swallowed too.

[linear-code]

ENG-11988