feat(lsp): Add TailwindCSS LSP server support

[iljod]

Summary

This PR adds support for TailwindCSS Language Server, enabling IDE-like features (autocomplete, hover info, diagnostics) for TailwindCSS projects.

Changes

• Added TailwindCSS LSP server configuration in packages/opencode/src/lsp/server.ts
• Auto-installs @tailwindcss/language-server when not found in the system
• Supports .css, .html, .htm, .jsx, .tsx, .vue, .svelte files
• Detects TailwindCSS projects by looking for tailwind.config.js/ts or postcss.config.js/ts
• Updated LSP documentation in packages/web/src/content/docs/lsp.mdx to include TailwindCSS entry

Testing

The implementation follows the same pattern as other auto-installed language servers (Vue, Svelte, etc.) in the codebase.

Fixes #8518

[github-actions]

Hey! Your PR title Add TailwindCSS LSP server support doesn't follow conventional commit format.

Please update it to start with one of:

• feat: or feat(scope): new feature
• fix: or fix(scope): bug fix
• docs: or docs(scope): documentation changes
• chore: or chore(scope): maintenance tasks
• refactor: or refactor(scope): code refactoring
• test: or test(scope): adding or updating tests

Where scope is the package name (e.g., app, desktop, opencode).

See CONTRIBUTING.md for details.

[github-actions]

The following comment was made by an LLM, it may be inaccurate:

No duplicate PRs found

[github-actions]

Thanks for your contribution!

This PR doesn't have a linked issue. All PRs must reference an existing issue.

Please:

1. Open an issue describing the bug/feature (if one doesn't exist)
2. Add Fixes #<number> or Closes #<number> to this PR description

See CONTRIBUTING.md for details.