Fix v3 config loading with Jiti re-exports

[Dunqing]

Fixes: #431

Summary
The crash happens when a Tailwind v3 config is an ESM file that re‑exports from a workspace package which itself is loaded via Jiti (v2). Our plugin’s v3 loader used Tailwind’s loadConfig, which internally uses Jiti v1 and returns a Proxy. When that Proxy touches modules loaded via Jiti v2, the getters recursively call each other, causing RangeError: Maximum call stack size exceeded.

Where it happens

• In src/versions/v3.ts, the old path was loadConfig(jsConfig) (Tailwind v3’s loader). That loader uses Jiti v1 internally.
• The demo repo uses a config like tailwind.config.mjs that re‑exports @repo/tailwind-config. That package uses Jiti v2 (via unbuild’s stub), creating the v1/v2 Proxy recursion.

Why the fix works

• The fix bypasses Tailwind v3’s loadConfig and uses our own Jiti v2 import (createJiti(...).import(...)) directly. That eliminates the mixed Jiti versions and prevents the Proxy recursion, so the config loads normally.

All done by Codex. I improved it a little and confirmed that this works well in the reproduction in #431.

[Dunqing]

@Boshen cc