feat(bankai): bankai v10 — the isomorphic compiler & server on Vite 8

One command, zero config, and only the client ever bundles: v8 server
code is plain ESM that Node runs as-authored, so there is no server
build to rot (the lesson of v9).

- start: Vite middleware mode + HMR with per-request streaming SSR via
  ssrLoadModule; a virtual client entry generates the browser glue so
  the user writes exactly one isomorphic module (plan decision D5).
- build: client bundle via Vite 8/Rolldown, manifest-derived route
  assets in dist/bankai.json, service worker built with the precache
  list injected (choo-service-worker convention, manifest edition),
  brotli+gzip precompression of every text asset.
- serve: immutable caching + precompressed negotiation for hashed
  assets, 103 Early Hints (res.writeEarlyHints) with the route's assets
  before every page, streaming SSR, and a window.initialState tail with
  script-breakout-safe serialization and choo internals filtered out.
- inspect: raw/gzip/brotli size report.

Integration tests drive the real counter example through build and
serve, asserting the 103 interim response at the HTTP level.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_014NgfSjHE11oFpoSnLVKLXd

packages/bankai/lib/dev.js

@@ -0,0 +1,59 @@
+// bankai start — the dev server: Vite middleware mode for the module
+// graph and HMR, per-request streaming SSR of the same entry through
+// vite.ssrLoadModule so server code shares Vite's transforms and cache.
+
+import { createServer } from 'node:http'
+
+import bankaiPlugin, { CLIENT_URL } from './plugin.js'
+import { resolveApp } from './app.js'
+import { documentHead, documentTail } from './document.js'
+
+export default async function dev ({ entry, port = 8080, title = 'choo' }) {
+  const { createServer: createViteServer } = await import('vite')
+
+  const vite = await createViteServer({
+    appType: 'custom',
+    server: { middlewareMode: true },
+    plugins: [bankaiPlugin(entry)],
+    logLevel: 'warn'
+  })
+
+  const server = createServer((req, res) => {
+    vite.middlewares(req, res, async () => {
+      // not an asset Vite knows: this is a page navigation — SSR it
+      try {
+        const mod = await vite.ssrLoadModule(entry)
+        const app = resolveApp(mod, entry)
+        const state = {}
+
+        res.writeHead(200, { 'content-type': 'text/html; charset=utf-8' })
+        res.write(documentHead({
+          title,
+          scripts: ['/@vite/client', CLIENT_URL]
+        }))
+
+        for await (const chunk of app.toStream(req.url, state)) {
+          res.write(chunk)
+        }
+        res.end(documentTail(state))
+      } catch (err) {
+        vite.ssrFixStacktrace(err)
+        console.error(err)
+        if (!res.headersSent) res.writeHead(500, { 'content-type': 'text/plain' })
+        res.end('bankai dev error:\n\n' + (err.stack || err.message))
+      }
+    })
+  })
+
+  await new Promise((resolve) => server.listen(port, resolve))
+  return {
+    server,
+    vite,
+    port: server.address().port,
+    origin: `http://localhost:${server.address().port}`,
+    close: async () => {
+      await vite.close()
+      await new Promise((resolve) => server.close(resolve))
+    }
+  }
+}