Add middlewares support to pipeline HTTP trigger config

[Copilot]

Pipeline HTTP triggers only forwarded path and method to route registration, making it impossible to apply middleware (auth, rate-limit, etc.) to pipeline-triggered routes without reimplementing auth as custom pipeline steps.

Changes

• plugins/http/plugin.go: Forward middlewares field in PipelineTriggerConfigWrappers alongside existing path and method passthroughs
• plugins/http/plugin_test.go: Add TestPipelineTriggerConfigWrappers covering forwarding and omission cases

Pipeline triggers can now reference middleware modules identically to explicit workflows.http.routes:

pipelines:
  list-items:
    trigger:
      type: http
      config:
        path: /items
        method: GET
        middlewares: [auth-bearer, rate-limit]
    steps:
      - name: parse
        type: step.request_parse

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[Copilot]

Pull request overview

This PR enables pipeline HTTP triggers to apply the same per-route middleware chain available to explicit workflows.http.routes, by forwarding the middlewares field through the pipeline trigger config wrapper.

Changes:

• Forward middlewares from flat pipeline HTTP trigger config into the generated route config.
• Add unit tests validating middlewares forwarding and omission behavior for the wrapper.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
plugins/http/plugin.go	Extends the HTTP pipeline trigger config wrapper to pass through middlewares into the generated route.
plugins/http/plugin_test.go	Adds coverage ensuring middlewares is forwarded when provided and omitted when absent.