Add support for Vite 8 in @tailwindcss/vite

[RobinMalfait]

This PR adds support for Vite 8 when using the @tailwindcss/vite package.

From the package's perspective, not a lot had to change, just the vite peer dependency now has an additional ^8.0.0 version range.

Closes: #19789

Test plan

1. Existing tests pass
2. Manually tested in the ./playgrounds/vite playground
3. Added Vite 8 integration tests to verify that the plugin works with Vite 8

[coderabbitai]

Walkthrough

This pull request adds Vite 8 support to the Tailwind CSS Vite integration. The package peer dependency range is expanded to include ^8, the workspace catalog Vite entry is bumped to 8.0.0, and test suites are updated to include Vite 8 (including a parameterized SSR test covering ^5.3, ^6.0, ^7, and ^8). No public APIs or exported declarations were changed.

🚥 Pre-merge checks | ✅ 4

✅ Passed checks (4 passed)

Check name	Status	Explanation
Title check	✅ Passed	The PR title accurately summarizes the main objective: adding Vite 8 support to @tailwindcss/vite package.
Description check	✅ Passed	The PR description clearly explains the changes made (peer dependency update), testing approach, and references the related issue #19789.
Linked Issues check	✅ Passed	The PR fully addresses issue #19789 by adding ^8.0.0 to the vite peer dependency range, enabling Vite 8 compatibility and resolving installation failures.
Out of Scope Changes check	✅ Passed	All changes are directly related to Vite 8 support: peer dependency update, SSR test refactoring for multi-version testing, workspace catalog bump, and test additions for Vite 8 validation.

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📝 Coding Plan

• Generate coding plan for human review comments

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[coderabbitai]

Actionable comments posted: 1

🤖 Prompt for all review comments with AI agents

Verify each finding against the current code and only fix it if needed.

Inline comments:
In `@pnpm-workspace.yaml`:
- Line 11: The workspace dependency entry "vite: ^8.0.0" references an
unreleased Vite 8 and will break installs; change that entry to a stable release
(e.g., "vite: ^7.3.0" or "^7.3.1") or revert the line until Vite 8 is officially
released so pnpm can resolve the dependency; update the "vite: ^8.0.0" token
wherever it appears in the workspace config to the chosen stable version.

---

ℹ️ Review info

⚙️ Run configuration

Configuration used: Repository UI

Review profile: CHILL

Plan: Pro

Run ID: b8462ef6-57e9-4502-8203-13e000a569ce

📥 Commits

Reviewing files that changed from the base of the PR and between dfc449c and 787ff4d.

⛔ Files ignored due to path filters (1)

• pnpm-lock.yaml is excluded by !**/pnpm-lock.yaml

📒 Files selected for processing (4)

• integrations/vite/index.test.ts
• integrations/vite/ssr.test.ts
• packages/@tailwindcss-vite/package.json
• pnpm-workspace.yaml

[coderabbitai]

🧹 Nitpick comments (1)

integrations/vite/ssr.test.ts (1)

4-4: Minor: Consider consistent version format for readability.

The version strings mix formats: ^5.3 and ^6.0 include minor versions, while ^7 and ^8 omit them. This is functionally correct but slightly inconsistent.

💅 Optional: Align version format

-describe.each([['^5.3'], ['^6.0'], ['^7'], ['^8']])('Using Vite %s', (version) => {
+describe.each([['^5.3'], ['^6.0'], ['^7.0'], ['^8.0']])('Using Vite %s', (version) => {

🤖 Prompt for AI Agents

Verify each finding against the current code and only fix it if needed.

In `@integrations/vite/ssr.test.ts` at line 4, The test matrix in the
describe.each call (test suite "Using Vite %s") mixes version string formats;
make them consistent by normalizing all entries to the same style (either
include a minor patch like '^7.0' and '^8.0' to match '^5.3'/'^6.0' or drop
minors from the first two to use '^5'/'^6' for parity). Update the array passed
to describe.each (the list of version strings) so every element follows the
chosen format to improve readability and consistency.

🤖 Prompt for all review comments with AI agents

Verify each finding against the current code and only fix it if needed.

Nitpick comments:
In `@integrations/vite/ssr.test.ts`:
- Line 4: The test matrix in the describe.each call (test suite "Using Vite %s")
mixes version string formats; make them consistent by normalizing all entries to
the same style (either include a minor patch like '^7.0' and '^8.0' to match
'^5.3'/'^6.0' or drop minors from the first two to use '^5'/'^6' for parity).
Update the array passed to describe.each (the list of version strings) so every
element follows the chosen format to improve readability and consistency.

---

ℹ️ Review info

⚙️ Run configuration

Configuration used: Repository UI

Review profile: CHILL

Plan: Pro

Run ID: ac695073-5ced-4c71-8b93-878aa79939dd

📥 Commits

Reviewing files that changed from the base of the PR and between 3bf810f and 14603f9.

📒 Files selected for processing (1)

• integrations/vite/ssr.test.ts

[hansmbakker]

@RobinMalfait does this also deal with the changed LightningCSS behavior that is mentioned as a breaking change in https://stackoverflow.com/a/79879526?