helm: expose coding_cli_sidecars in chart (REMOTE-2107)

[seemeroland]

Summary

Exposes the coding_cli_sidecars worker config through the Helm chart so self-hosted Kubernetes deployments can point a harness (e.g. claude) at a custom or internal Claude Code binary wrapper image declaratively.

Background

PR #92 added the coding_cli_sidecars config to the worker (internal/config, main.go) and documented it in the README, and it shipped in release v2026-07-09-15-18-23. However, the Helm chart (charts/oz-agent-worker) was never updated to render this field. Deployments that install via the chart could not set it declaratively and had to fall back to setup-command workarounds (as IMC did with their imc-claude wrapper).

Changes

• values.yaml: add kubernetesBackend.codingCliSidecars (defaults to {}) with an explanatory comment.
• templates/configmap.yaml: render coding_cli_sidecars into the worker config.yaml under backend.kubernetes, following the existing extraLabels/extraAnnotations {{- with ... }} pattern. Omitted entirely when unset.
• Chart.yaml: bump chart version 0.1.0 → 0.2.0.
• README.md: note the new chart value in the Helm section.

Example

kubernetesBackend:
  codingCliSidecars:
    claude: "registry.internal.example.com/imc-claude:v1"

renders to:

backend:
  kubernetes:
    coding_cli_sidecars:
      claude: "registry.internal.example.com/imc-claude:v1"

Validation

• helm lint ./charts/oz-agent-worker passes (matches CI).
• helm template renders coding_cli_sidecars correctly nested under backend.kubernetes.
• Default render (no override) omits the key entirely.

Resolves REMOTE-2107.

Conversation: https://staging.warp.dev/conversation/4694de2e-a0d9-4b1e-ac35-c6cdff087f87
Run: https://oz.staging.warp.dev/runs/019f47d6-d577-7792-bc76-f13f69015c8a

This PR was generated with Oz.