v1.15.0 — Validation, completed

Validation, completed — this release closes the gap between what a route
documents and what it enforces, and fixes the codegen type-safety holes
that pushed consumers back to hand-written types.

Added

• Path-parameter schemas + validation — defineRoute now accepts
  request: { params }, so :id and friends are validated by the same Zod
  schema that documents them, with a structured 422 on mismatch. Works across
  Express, Fastify, Hono, Koa, and NestJS — no more hand-rolled requireUuid
  helpers repeated on every route.
• Request write-back. Opt in with validate: { writeback: true } and the
  parsed payload — Zod coercions and .default()s applied — is written back
  onto req.body / req.query / req.params, so the handler reads coerced
  values instead of re-parsing them. (Koa and Hono expose coerced path params
  via ctx.state.doctreenValidated / c.get('doctreenValidated').)
• Dev-mode response assertion. validate: { response: 'warn' | 'throw' }
  checks the handler's response against the declared Zod response schema —
  'warn' logs a mismatch and passes through, 'throw' surfaces a 500 in
  development. Never coerces the response.
• Status-keyed responses. response: { 201: schema, 200: schema } documents
  each status with its own schema and drives the OpenAPI export; the plain
  response: schema form still means 200.
• defaultErrors config. Declare shared error responses (401 / 403 / 422 …)
  once — they merge into every route, with the route's own errors winning on a
  status conflict.
• Standard DoctreenValidationError envelope. Validated routes document
  their 422 { error, issues[] } body as a named component, so codegen emits a
  DoctreenValidationError type and clients stop guessing the error shape.
• Offline OpenAPI emit. getOpenApiDocument(app) (on every adapter) and the
  new doctreen emit-openapi CLI build a static openapi.json without starting
  a server, so codegen and CI can run fully offline.

Fixed

• defineSchema now works with Zod schemas. Named schemas were matched by
  object identity, which Zod→SchemaNode conversion breaks — so Zod-defined named
  schemas fell through to anonymous Schema1 / Schema2 types in codegen. They
  now emit $ref: '#/components/schemas/<name>' and codegen produces
  interface User, at the top level, nested, and inside arrays.
• Deep schemas no longer collapse to unknown. The Zod conversion depth cap
  was raised from 5 to 12, so deep-but-non-recursive trees (menu → categories →
  items → variants → options) keep their leaf types. Recursion is best expressed
  with defineSchema, which now emits a terminating $ref.