Implement Domain Model First architecture for JSON-based Slurm command parsing

[Copilot]

Implements Approach 2 (Domain Model First) for migrating from string parsing to JSON output (--json flag) with clear separation between data retrieval and parsing. Provides complete architecture for future-proofing against multiple data sources (binaries, slurmrestd REST API, files).

Current Architecture

• Fetchers call Slurm binaries → custom parsers extract key=value pairs → TableData (rows/columns)
• OpenAPI schemas (v0.0.40-43) and generated models already present in internal/slurmapi/
• Provider pattern: BaseProvider[T] with concrete implementations (JobsProvider, NodesProvider, etc.)

Implemented Architecture

Five-layer separation of concerns:

1. Data Sources (internal/datasource/) - SlurmDataSource interface with implementations:

   • BinaryJSONSource - Calls Slurm binaries with --json flag
   • FileSource - Reads JSON from files (testing/offline mode)
   • RestAPISource - Placeholder for future slurmrestd support

2. JSON Parsers (internal/parser/) - Convert OpenAPI models to domain models:

   • ParseJobsJSON() - V0043OpenapiJobInfoResp → domain.Jobs
   • ParseNodesJSON() - V0043OpenapiNodesResp → domain.Nodes
   • ParsePartitionsJSON() - V0043OpenapiPartitionResp → domain.Partitions

3. Domain Models (internal/domain/) - API-independent business entities:

   • domain.Job - Comprehensive job representation (40+ fields)
   • domain.Node - Complete compute node model
   • domain.Partition - Partition configuration and limits

4. Adapters (internal/model/adapters.go) - Transform domain models to display format:

   • JobsToTableData() - Converts domain.Jobs → TableData
   • NodesToTableData() - Converts domain.Nodes → TableData
   • PartitionsToTableData() - Converts domain.Partitions → TableData

5. V2 Providers - Demonstrate the complete pattern:

   • JobsProviderV2, NodesProviderV2, PartitionsProviderV2
   • Flow: DataSource → Parser → Domain Model → Adapter → TableData

Key Benefits

• Clear separation: Data retrieval, parsing, and presentation are completely independent
• Multiple sources: Easy to switch between binary calls, REST API, or file-based sources
• Type safety: Uses generated OpenAPI models for JSON unmarshaling
• Future-proof: Adding slurmrestd support requires only implementing RestAPISource
• Backward compatible: V1 providers remain functional; V2 providers coexist as examples
• Testable: Each layer can be tested independently

Documentation

Complete architecture documentation added in docs/architecture-json-migration.md including:

• Detailed layer explanations
• Usage examples
• Migration path
• Design decisions
• Next steps for production use

Testing

• ✅ All code compiles and builds successfully
• ✅ Type-safe JSON parsing using generated OpenAPI models
• ✅ Clean separation verified across all layers
• ✅ V2 providers demonstrate complete data flow

Future work: Add unit tests for parsers, integration tests with mock data, gradual V1 to V2 migration.

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[Antvirf]

@copilot approach 2 pls

[Copilot]

@copilot approach 2 pls

Approach 2 (Domain Model First) implemented! ✅

Complete architecture with 5 clean layers:

1. Data Sources - SlurmDataSource interface with BinaryJSONSource (uses --json), FileSource (testing), and RestAPISource placeholder
2. JSON Parsers - Convert OpenAPI models → domain models (ParseJobsJSON, ParseNodesJSON, ParsePartitionsJSON)
3. Domain Models - API-independent business entities (domain.Job, domain.Node, domain.Partition)
4. Adapters - Transform domain → TableData for existing UI
5. V2 Providers - Demonstrate the pattern (JobsProviderV2, NodesProviderV2, PartitionsProviderV2)

Clear separation achieved:

• Getting JSON: Data source implementations (binary/REST/file)
• Parsing JSON: Parser layer uses generated OpenAPI models
• Internal structure: Domain models are display-agnostic, adapters handle table conversion

Future-proof: Adding slurmrestd support = just implement RestAPISource ✨

See docs/architecture-json-migration.md for complete details.

Commits: 0248506 (core), 0fd3c43 (providers), 16b1336 (docs)