Update existing agent CLI modules to reference `task.prompt`

[johnstcn]

Following #979, update existing templates and modules that define a coder_ai_task resource to reference task.prompt instead of data.coder_parameter.ai_prompt.value:

• https://github.com/coder/registry/tree/main/registry/coder/modules/agentapi/
• https://github.com/coder/registry/tree/main/registry/coder-labs/templates/tasks-docker
• https://github.com/coder/registry/tree/main/registry/sharkymark/templates/docker-claude

Note: the following modules reference agentapi:

registry/coder-labs/modules/auggie
registry/coder-labs/modules/copilot
registry/coder-labs/modules/codex
registry/coder-labs/modules/cursor-cli
registry/coder-labs/modules/gemini
registry/coder-labs/modules/sourcegraph-amp
registry/coder/modules/goose
registry/coder/modules/claude-code
registry/coder/modules/amazon-q

Also:

• coder/dogfood template https://github.com/coder/coder/tree/main/dogfood/coder (PR: chore: update coder/dogfood template to reference coder_task.prompt coder#20416)

Note that the example docker tasks template in coder/coder must remain 'old-style' for the moment. (PR: coder/coder#20420)