After v0.1.4: refresh the AI provider how-to prerequisite, and trust only Coder's own 404 in the CoderTemplateTest and pool member confirm reads #351

Summary

Two small follow-ups after the v0.1.4 release.

1. Stale prerequisite in the AI provider how-to. docs/how-to/manage-ai-providers.md ("Before you start") still says "An operator release after v0.1.3 … its ghcr.io/coder/coder-k8s:latest image is v0.1.3 until the next release". v0.1.4 is out, and :latest now points to 0.1.4. Replace it with "coder-k8s v0.1.4 or later" and keep the advice to pin the image to the release version. Also fix the CoderRejected row, which says "Coder rejected the create request". The sync PATCH also returns it ("the create or update request").
2. CoderTemplateTest confirm path trusts any 404. internal/controller/codertemplatetest_confirm.go and the lookup in codertemplatetest_controller.go use the plain isCoderNotFound. After the settle window, a 404 from a proxy or a wrong route reads as "no workspace", so the controller clears the marker and can leave a ktt- workspace behind. It never deletes a wrong workspace. Use isCoderResourceNotFound (from 🤖 fix: check a CoderAIProvider's provider ID before Coder calls, and trust only Coder's own delete 404 #325), as the CoderAIProvider paths now do. The pool member confirmPoolMemberCreate has the same pattern; fix it in the same PR (it must be fixed before PR 12 of CoderWorkspacePool: prebuilt workspaces with a scale subresource #153 registers that reconciler). Add tests for an HTML 404 and for Route not found..

Found by the final assessment of #344 and the v0.1.4 notes review.

Generated with xum • Model: anthropic:claude-opus-5-5 • Thinking: medium