feat(hono): one fetch adapter, and Hono on top of it

[cport1]

Closes #727 and #736.

The duplication (#736)

Express, Fastify and Next.js had each grown their own copy of the same decision tree: skip-path matching, monitor-versus-enforce, honeytoken arming, the 429 with a Retry-After, fail-open error handling.

Three copies is three places for the branch that matters to be subtly different — and it already had been. The leftmost-X-Forwarded-For bug (#725) survived in two adapters after the WordPress plugin had fixed the same class of bug, precisely because there was no one place to fix it.

createFetchGuard() is that tree written once, over WHATWG Request/Response:

const guard = createFetchGuard({ mode: 'enforce', rules: [tripwire()] });

export default {
  async fetch(request: Request): Promise<Response> {
    const { response } = await guard.check(request);
    if (response) return response;
    return guard.decorate(await handle(request));
  },
};

It's also the answer to "which framework do you support?". The issue's suggestion was to start with a generic Request recipe rather than adding packages speculatively, and that's what this is: Bun, Deno, Astro, Nitro, SvelteKit and Remix all work through it with no package at all, documented in the README.

I did not refactor Express/Fastify/Next onto it in this PR. Their honeytoken injection hooks into framework-specific response streaming — Express intercepts res.write/res.end, Fastify uses an onSend hook — and that machinery carries hard-won detail (the Angular SSR headersSent case, Content-Length correction). Rewriting it on top of a shared core is a behaviour-preserving refactor that deserves its own PR with those tests as the contract, not a rider on a feature. Filed as a follow-up rather than left implied.

Hono (#727)

Hono gets a real package because it has a middleware contract worth fitting, and because it's the default on Workers, Bun and Deno — the runtimes the rest of our stack already fronts. The Cloudflare edge sensor has been tagging every request it forwards and readEdgeVerdict() exists so the origin can act on that tag; there was no origin middleware there to do it.

app.use('*', webdecoy({ rules: [tripwire()], skipPaths: ['/health'] }));

c.get('webdecoy') carries the decision — in monitor mode, which is the default, that's the only place the verdict surfaces, so there's a test for it.

Honeytoken injection works through the fetch shape. The Express implementation needed response-stream interception to get there; reading and rewriting a Response is enough, so Hono got it for free — including Content-Length correction, which has its own test because a stale one truncates the body at the client.

Verification

12 new tests through a real Hono app via app.request() — the same fetch-shaped entry point Workers and Bun call, so this exercises the actual runtime contract rather than a mock. 406 tests total, 20/20 turbo tasks. check:edge now covers three entry points (core, Next.js, Hono); Hono is externalised in the gate alongside next/express/fastify.