fix(devtools): handle RPC registration regardless of module order

[nicokempe]

🔗 Linked issue

resolves #216, tested through the playground where it fixed the issue, but definitely open to feedback

❓ Type of change

• 📖 Documentation (updates to the documentation or readme)
• 🐞 Bug fix (a non-breaking change that fixes an issue)
• 👌 Enhancement (improving an existing functionality)
• ✨ New feature (a non-breaking change that adds functionality)
• 🧹 Chore (updates to the build process or auxiliary tools and libraries)
• ⚠️ Breaking change (fix or feature that would cause existing functionality to change)

📚 Description

This PR fixes a DevTools integration bug where the RPC namespace (nuxt-a11y-rpc) was not registered if @nuxt/devtools initialized before @nuxt/a11y.

Root cause

The DevTools RPC handlers were registered only inside onDevToolsInitialized().
If DevTools had already finished initialization before this module executed (which happens when @nuxt/devtools appears earlier in modules: []), the hook never fired and the RPC handlers were never registered.

This resulted in DevTools errors such as:

[nuxt-devtools] RPC error on executing "nuxt-a11y-rpc:connected"
[birpc] function "nuxt-a11y-rpc:connected" not found

The a11y runtime itself continued to work correctly, but the DevTools panel was partially broken.

Solution

The RPC registration logic is now resilient to initialization order by:

• Registering RPC handlers via onDevToolsInitialized() (normal path)
• Performing a best-effort immediate registration attempt to handle cases where DevTools was already initialized
• Guarding against duplicate registration

This ensures the DevTools RPC namespace is always registered, regardless of module order.

Why this matters

• Fixes broken DevTools integration in existing / legacy projects that explicitly include @nuxt/devtools in modules: []
• Fully backward-compatible and non-breaking

[pkg-pr-new]

Open in StackBlitz

npm i https://pkg.pr.new/nuxt/a11y/@nuxt/a11y@217

commit: 7ba6938

[nicokempe]

not required anymore due to nuxt/devtools#919