Generalize native Helm runner and post-renderer config

[vigneshrajsb]

What changed

• add native Helm support for a configurable runner image
• add generic post-renderer config with enabled, command, and args
• merge native Helm config from global defaults, chart config, and service config with service overrides winning
• validate merged native Helm config rather than only raw service config
• add tests for default behavior, global config, overrides, disable semantics, and manifest generation from lifecycle YAML

Why

This lets native Helm deployments support custom runner images and Helm post-renderers without relying on CI-specific deploy steps.

Validation

• pnpm exec jest src/server/lib/config/__tests__/ConfigBuilder.test.ts --runInBand
• pnpm exec jest src/server/lib/nativeHelm/__tests__/helm.test.ts --runInBand
• pnpm test

[nickhodaly-ud]

Duplicate HelmPostRendererConfig interface

This interface is defined in three separate places with identical shapes:

• src/server/lib/config/ConfigBuilder.ts#L20-L24
• src/server/lib/nativeHelm/utils.ts#L46-L50
• src/server/services/types/globalConfig.ts#L119-L123

These will drift over time. We should pick one canonical location (probably globalConfig.ts since it already defines NativeHelmConfig) and import it in the other two files.

[vigneshrajsb]

good call human! fixed