feat: add typed route generator for Hono (generateRoutes v2)

[stackbilt-admin]

Problem

generateRoutes currently emits handler bodies as plain strings, requiring manual paste or eval at the consumer site. This is incompatible with typed Cloudflare Workers frameworks.

FoodFiles uses Hono with a typed app environment (Hono<AppEnv>). String-emitted handlers:

• Cannot be type-checked by tsc
• Cannot be composed with AppEnv generics (bindings, variables)
• Cannot be tree-shaken or statically analyzed by bundlers

This blocks any automated route wiring for phase-0 consumers and makes generateRoutes unusable in a typed Hono project.

Acceptance Criteria

• generateRoutes returns importable route handler functions (or a Hono router instance) instead of strings
• Output is parameterized by an Env generic so consumers can pass Hono<AppEnv> context through
• Generated handlers preserve the full input/output types derived from the contract schema
• A toHonoRouter<Env>(contract, handlers) helper (or equivalent) is exported from the package
• At least one generated route passes tsc --strict in an isolated test fixture
• Existing generateRoutes string-output API is deprecated with a migration note in the changelog

Context

FoodFiles is the designated phase-0 consumer for @stackbilt/contracts. The pantry and recipe routes are the primary integration targets. Without typed route generation, the contract layer cannot replace the hand-rolled Zod schemas in services/pantry.ts and services/recipe.ts.

Ref: CONTRACT-1 gap analysis (phase-0 integration audit)