fix/docs/test: bulk fixes for #372, #374, #375, #376, #378

[mathildabot]

Summary

Bulk fix for 5 open issues.

Changes

fix: add kubebuilder RBAC marker for coordination.k8s.io/leases (closes #372)

Adds the missing //+kubebuilder:rbac marker for coordination.k8s.io/leases to cmd/main.go. Without this, make manifests could silently drop the lease permission if role.yaml is regenerated from scratch.

test: add unit tests for controller infrastructure helpers (closes #374)

Extends internal/controller/helpers_test.go with tests for previously untested helper functions, improving coverage of the controller infrastructure layer.

docs: add troubleshooting guide (closes #375)

Adds docs/troubleshooting.md covering common issues: pod not starting, CRD not found, certificate not signing, CA Init-Job failing, webhook errors.

docs: add Helm values reference documentation (closes #376)

Adds docs/reference/helm-values.md documenting all values for openvox-operator and openvox-stack charts. Both docs are linked in mkdocs.yml nav.

fix: replace floating :latest image tag defaults with chart appVersion (closes #378)

• charts/openvox-operator/values.yaml: tag defaults to "" (uses chart appVersion)
• charts/openvox-stack/values.yaml: same pattern
• api/v1alpha1/config_types.go: default image tag changed from latest to ""

[mathildabot]

Superseded by #390