fix(dev): use the websocket adapter of the runtime the dev worker runs in

[pi0x]

WebSockets in dev only worked on Node: both dev entries (nitro dev and the Vite dev worker) imported crossws/adapters/node directly, so running under bun --bun crashed with [crossws] Using Node.js adapter in an incompatible environment.

The dev entries now export crossws { resolve } options through env-runner's websocket entry field, and env-runner installs the adapter of the runtime the worker actually runs in. The Vite worker entry only declares it when features.websocket is enabled, and resolving hooks now waits for the app entry, which also fixes a WebSocket sent as the very first request failing on Node.

test/vite/websocket.test.ts starts real dev servers in a child process and echoes over a WebSocket for Vite dev and nitro dev, under Node and bun --bun. Three of the four cases fail on main (nitro dev on Node already worked). nitro dev under Deno was checked by hand.

Combines #4376 and #4597. The parent dev server WebSocket proxy and the hook caching from #4376 are not needed: current Bun proxies the upgrade through node:http fine, and crossws 0.4.12 already caches resolved hooks per connection.

Fixes #3939

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Project	Deployment	Actions	Updated
nitro.build	Ready	Preview	Oct 3, 2026 2:33pm UTC

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📒 Files selected for processing (7)

• src/build/vite/_dev-worker.ts
• src/presets/_nitro/runtime/nitro-dev.ts
• src/runtime/internal/vite/dev-entry.mjs
• src/runtime/internal/vite/dev-worker.mjs
• test/vite/websocket-fixture/routes/ws.ts
• test/vite/websocket-fixture/vite.config.ts
• test/vite/websocket.test.ts

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