fix: add Tailwind v4 @theme inline guidance to prevent v3 patterns

[rubenmarcus]

Summary

• Adds comprehensive Tailwind v4 @theme inline guidance to the context builder preamble and spec generator
• Prevents agents from generating manual utility classes (.bg-brand { background-color: ... }) that break opacity modifiers, gradients, and other auto-generated utilities
• Adds Vite-specific guidance (@tailwindcss/vite vs @tailwindcss/postcss)
• Documents bg-color/opacity syntax, tw-animate-css, and no-manual-reset rules

Test plan

• Run ralph-starter run with a Tailwind v4 project and verify agent uses @theme inline for custom colors
• Verify generated CSS doesn't contain manual utility class definitions
• Check that opacity modifiers (bg-brand/80) work correctly

Closes #211

🤖 Generated with Claude Code

[github-actions]

✔️ Bundle Size Analysis

Metric	Value
Base	1926.12 KB
PR	1927.54 KB
Diff	1.41 KB (0%)

Bundle breakdown

156K	dist/auth
32K	dist/automation
4.0K	dist/cli.d.ts
4.0K	dist/cli.d.ts.map
16K	dist/cli.js
12K	dist/cli.js.map
492K	dist/commands
28K	dist/config
4.0K	dist/index.d.ts
4.0K	dist/index.d.ts.map
4.0K	dist/index.js
4.0K	dist/index.js.map
560K	dist/integrations
84K	dist/llm
736K	dist/loop
188K	dist/mcp
32K	dist/presets
92K	dist/setup
36K	dist/skills
392K	dist/sources
76K	dist/ui
84K	dist/utils
336K	dist/wizard

[greptile-apps]

Greptile Summary

Adds comprehensive Tailwind CSS v4 @theme inline guidance to prevent agents from manually defining utility classes that break opacity modifiers and gradient utilities.

Key Changes:

• Added @theme inline examples and best practices to context-builder.ts preamble (shown to agents during execution)
• Enhanced Tailwind v4 setup notes in spec-generator.ts for wizard-generated specs
• Clarified Vite vs non-Vite setup (@tailwindcss/vite vs @tailwindcss/postcss)
• Documented bg-color/opacity syntax (replacing deprecated bg-opacity-*)
• Added animation library guidance (tw-animate-css not tailwindcss-animate)
• Explicitly warns against manual utility class definitions

Impact:
This ensures agents use CSS-based configuration correctly and avoid common Tailwind v4 migration pitfalls that break utility functionality.

Confidence Score: 5/5

• Safe to merge - documentation-only changes that improve agent guidance
• This PR only adds documentation and guidance text to help agents use Tailwind v4 correctly. No logic changes, no breaking changes, no security concerns. The changes are well-structured, accurate, and address a real problem (agents generating manual utility classes instead of using @theme inline).
• No files require special attention

Important Files Changed

Filename	Overview
src/loop/context-builder.ts	Added comprehensive Tailwind v4 @theme inline guidance to preamble with Vite-specific setup instructions and opacity syntax
src/wizard/spec-generator.ts	Enhanced Tailwind v4 setup notes in generated specs with @theme inline examples and best practices

_{Last reviewed commit: 7d2e711}