[DS] fabric_data_agent

[OrBaubergMicrosoft]

📝 Description

When managing Microsoft Fabric infrastructure as code,
I want to read existing Data Agent resources via Terraform data sources,
so I can reference Data Agent configurations in my Terraform plans without managing their lifecycle.

Related resource issue: #895

🔬 Details / References

• Data Source Name: fabric_data_agent (singular) / fabric_data_agents (plural list)
• API documentation:
  • https://learn.microsoft.com/rest/api/fabric/dataagent/items/get-data-agent
  • https://learn.microsoft.com/rest/api/fabric/dataagent/items/list-data-agents
• Definition article: https://learn.microsoft.com/rest/api/fabric/articles/item-management/definitions/data-agent-definition
• SDK Package: github.com/microsoft/fabric-sdk-go/fabric/dataagent (import alias: fabdataagent)
• ItemType Constant: fabcore.ItemTypeDataAgent ("DataAgent")
• Item Archetype: definition-properties
• Properties DTO fields:
  • OneLakeRootPath *string — OneLake path to the DataAgent root directory (read-only)
• Definition format: JSON
• Definition Paths:
  • Files/Config/data_agent.json (format: JSON) — required — top-level data agent configuration
  • Files/Config/draft/stage_config.json (format: JSON) — required — stage configuration (AI instructions)
  • Files/Config/draft/{dataSourceType}-{dataSourceName}/datasource.json (format: JSON) — optional — data source configuration
  • Files/Config/draft/{dataSourceType}-{dataSourceName}/fewshots.json (format: JSON) — optional — few shot examples
  • Files/Config/publish_info.json (format: JSON) — optional — publish info (if published)
  • Files/Config/published/stage_config.json (format: JSON) — optional — published stage configuration
  • Files/Config/published/{dataSourceType}-{dataSourceName}/datasource.json (format: JSON) — optional
  • Files/Config/published/{dataSourceType}-{dataSourceName}/fewshots.json (format: JSON) — optional
• Estimated complexity/effort: moderate
• Preview: no
• SPN Supported: yes
• Related resources/data-sources:
  • fabric_workspace (required parent)
  • fabric_data_agent resource ([RS] fabric_data_agent #895)

🚧 Potential Terraform Configuration

# Singular data source — look up by ID or display_name
data "fabric_data_agent" "example" {
  display_name = "example"
  workspace_id = fabric_workspace.example.id
}

# Plural data source — list all Data Agents in a workspace
data "fabric_data_agents" "all" {
  workspace_id = fabric_workspace.example.id
}

☑️ Acceptance Criteria

• Can read Data Agent by ID
• Can read Data Agent by display_name
• Can list all Data Agents in a workspace
• Properties (one_lake_root_path) are correctly mapped from SDK response

✅ Definition of Done

• Data Transfer Objects (DTOs)
• Data-Source Implementation (singular + plural)
• Data-Source Added to Provider
• Unit Tests for Happy path
• Unit Tests for Error path
• Acceptance Tests
• Example in the ./examples folder
• Schema documentation in code
• Updated auto-generated provider docs with task docs