feat(001): implement deploy-time external providers L1

[rhuss]

Summary

This PR implements the core functionality for external provider injection at deployment time, enabling custom LlamaStack providers via container images.

Spec Reference: specs/001-deploy-time-providers-l1/spec.md

CRD Extensions

• ExternalProvidersSpec organized by API type (inference, safety, agents, etc.)
• ExternalProviderRef with providerId, image, imagePullPolicy, config
• ExternalProviderStatus for phase-based tracking (Pending, Installing, Ready, Failed)

New Packages

Provider Package (pkg/provider/)

• ProviderMetadata struct matching lls-provider-spec.yaml schema
• LoadProviderMetadata and ParseProviderMetadata functions
• ValidateMetadata with comprehensive validation rules
• API name normalization between CRD and config.yaml formats

Deploy Package Extensions (pkg/deploy/)

• GenerateInitContainers for provider installation
• GenerateExtractConfigInitContainer for base config extraction
• Volume helpers for shared emptyDir configuration
• RunYamlConfig struct and MergeExternalProviders function
• GenerateConfig orchestrating the full merge process

Binary (cmd/generate-config/)

• CLI tool for config generation init container
• Reads provider metadata and merges into base config.yaml

Controller Integration

• configureExternalProviders in resource_helper.go
• Status tracking functions in status.go
• PYTHONPATH and config path updates for main container

Dockerfile Updates

• Builds and includes generate-config binary at /generate-config

Example Usage

apiVersion: llama.meta.com/v1alpha1
kind: LlamaStackDistribution
metadata:
  name: my-llsd
spec:
  server:
    distribution:
      name: ollama
    externalProviders:
      volumeSizeLimit: "2Gi"
      inference:
        - providerId: custom-vllm
          image: registry.example.com/custom-vllm-provider:v1.0
          config:
            url: https://my-vllm-endpoint.example.com
      safety:
        - providerId: custom-safety
          image: registry.example.com/safety-provider:v1.0

Test plan

• Unit tests pass for pkg/provider/ package
• Unit tests pass for pkg/deploy/ package (initcontainer, runyaml)
• Integration test with single external provider
• Integration test with multiple providers across different API types
• Verify PYTHONPATH is correctly updated in main container
• Verify config.yaml is correctly merged with external provider entries
• Verify status tracking reflects provider installation phases

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Assisted-By: 🤖 Claude Code