feat: expose container devices to templates

[JamBalaya56562]

Summary

Exposes container device passthrough (HostConfig.Devices) to templates, reimplementing the stale PR #277 against the current internal/ layout.

• Adds a Device{PathOnHost, PathInContainer, Permissions} type and a Devices []Device field on RuntimeContainer.
• Populates it in getContainers, mirroring the existing Mounts loop. go-dockerclient's Device.CgroupPermissions is mapped to Device.Permissions.

Use case: discovering forwarded device nodes (webcams, USB-serial adapters, etc.) from templates.

Notes

• The populate loop iterates the nil-safe local copy of HostConfig (introduced in fix: avoid panic on nil container Config/NetworkSettings/HostConfig #748) instead of dereferencing container.HostConfig directly, so a container inspected with a nil HostConfig cannot panic.
• The unrelated t.Fatal→t.Fatalf churn from the original PR is dropped.
• HostConfig.Devices has been stable in go-dockerclient since 2018, so no dependency change is required.

Tests

Added TestGetContainersDevices, which drives getContainers against a mock daemon returning a device and asserts the populated Devices. Documented the Device struct and a JSON example in the README.

Reimplements #277

🤖 Generated with Claude Code

[buchdag]

@JamBalaya56562 please flag AI-generated PR explicitly in the PR description (ie "🤖 Generated with Claude Code" like in this PR) and add the AI agent as co-author of the commits.

[JamBalaya56562]

Done — added the Co-Authored-By: Claude Opus 4.8 trailer to the commit and the 🤖 Generated with [Claude Code](https://claude.com/claude-code) note to the PR description. I also rebased onto the latest main. Thanks for the review!

[Copilot]

Pull request overview

This PR adds support for exposing Docker device passthrough configuration (HostConfig.Devices) in the emitted RuntimeContainer context so templates can render forwarded device nodes (e.g., USB serial adapters, webcams).

Changes:

• Introduces a Device type and adds Devices []Device to RuntimeContainer (context + README documentation).
• Populates RuntimeContainer.Devices in getContainers by mapping docker.Device fields (including CgroupPermissions → Permissions).
• Adds a unit test covering device extraction via a mock Docker daemon response.

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 1 comment.

File	Description
README.md	Documents the new Devices field, Device struct, and provides a JSON example.
internal/context/context.go	Adds Device and wires Devices []Device into RuntimeContainer.
internal/generator/generator.go	Populates RuntimeContainer.Devices from inspected container HostConfig.Devices.
internal/generator/generator_test.go	Adds TestGetContainersDevices to assert device passthrough is emitted into context.

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