Deprecate and remove `@stacksjs/router` (now a thin wrapper around `@stacksjs/bun-router`)

[glennmichael123]

storage/framework/core/router/ (@stacksjs/router) was originally a Stacks-specific layer over bun-router that added action-string handlers and route-file loading. With the current @stacksjs/bun-router@0.0.5+, most of those features are now upstream:

• String action handlers ('Actions/Foo') — already in bun-router (handler-resolver.ts:92)
• File-based routing — already in bun-router (file-based-routing.ts)
• Route grouping, class handlers, response factory, cors, Middleware, rate limiting — all in bun-router

The wrapper now provides essentially:

• A pre-instantiated route singleton (vs. bun-router's router)
• runWithRequest / request() AsyncLocalStorage helpers
• Named-route url(name, params) generation
• An object-shaped routes-registry loader (app/Routes.ts map → file imports)
• trackQuery for the debug error page
• Action validations schema hook

Proposal

1. Land request context + named-route URLs in bun-router upstream — see stacksjs/bun-router#874.
2. Once those land, do the migration in this repo:
   • Rewrite ~22 import sites from @stacksjs/router → @stacksjs/bun-router for pass-throughs (Router, cors, response, Middleware, Request type, rate-limit helpers, serve).
   • Switch the remaining ~8 sites that use context/url to the new bun-router APIs.
   • Keep trackQuery and Action validations as small Stacks-side helpers (they're project-specific; see notes in stacksjs/bun-router#874 for rationale).
   • Replace the object-shaped app/Routes.ts registry with a tiny app-side loader, OR drop the registry pattern and import route files directly in dev/api.ts. Either works.
3. Delete storage/framework/core/router/ workspace package.
4. Update CLI scaffolds (routes/api.ts template, dev-server entrypoints, etc.) to import from @stacksjs/bun-router directly.

Why now

• The two packages overlapping has caused real pain: routes/api.ts defaults to import { route } from '@stacksjs/bun-router', which doesn't export route — a user-visible 404 on every endpoint of a fresh app (see #1835).
• Type-resolution edge cases in the wrapper bleed into editor errors (TS7034 Variable 'route' implicitly has type 'any') when bun-router's published .d.ts is incomplete (see stacksjs/dtsx#3090 for the related dts-emission bug).
• Deprecating the wrapper removes the ambiguity and reduces maintenance surface.

Migration risk

Low-medium. Mechanical for pass-through imports. The substantive work is just porting ~70 LOC of glue into bun-router (request context + named URLs) and ~80 LOC of stacks-specific helpers (validations + trackQuery + optional registry loader) staying in this repo. No runtime behavior change for end users.

Blocked on

stacksjs/bun-router#874 — request context + named-route URL helpers landing upstream.