fix: adjust renderBuiltUrl resolution for relative pathing

[ryok90]

Fix renderBuiltUrl API signature in pluginAddEntry

Fixes #384

Problem

PR #373 added renderBuiltUrl support but had two critical bugs:

1. Incomplete API signature: Called renderBuiltUrl(file) with only one parameter, but Vite expects renderBuiltUrl(filename, options)
2. Missing return type handling: Didn't handle the three possible return types (string, {runtime}, {relative})

This broke compatibility with any renderBuiltUrl implementation that depends on the options parameter, causing "Cannot destructure property of undefined" errors.

Solution

Updated src/plugins/pluginAddEntry.ts (lines 135-191) to:

1. Call with correct signature: Pass both filename and options object with hostId, hostType, type, and ssr parameters
2. Handle all return types:
   • string → Use directly
   • {relative: true} → Use filename without base prefix
   • {runtime: "code"} → Warn and fallback (incompatible with HTML <script src="">)
   • undefined → Fallback to default base + file
3. Per-file resolution: Resolve path for each HTML file with correct hostId

Testing

• ✅ Build succeeds
• ✅ All unit tests pass (61 tests)
• ✅ vite-vite example builds successfully
• ✅ Tested with reproduction from [Bug]: #384 - build completes without errors
• ✅ Backward compatible (works without renderBuiltUrl configured)

Preserves PR #373

The fix maintains the original functionality from #373 (issue #372) - renderBuiltUrl transformations are correctly applied to hostInit script tags.

[gioboa]

Thank you @ryok90 nice fix 💪