Retrieves all external identifiers associated with a project.

Business Context:
External identifiers allow Elios Fund projects to be linked with records
in external systems, enabling seamless data synchronization and cross-platform
integrations. Each project can have multiple external identifiers for different
systems and purposes.

External Identifier Purpose:

• CRM Integration: Link projects with CRM system records
• ERP Systems: Connect with enterprise resource planning platforms
• Solar Design Tools: Associate with design software project IDs
• Utility Systems: Map to utility company tracking numbers
• Partner Platforms: Reference partner system project identifiers
• Third-party APIs: Enable integration with external service providers

External Identifier Structure:

• Key: Identifies the external system or purpose (e.g., "salesforce_id", "sunobi_project")
• Value: The actual identifier used in the external system
• Source: How the identifier was created (API, manual entry, import)

Common External Identifier Keys:

• salesforce_id: Salesforce CRM project record ID
• sunobi_project: Sunobi design platform project identifier
• utility_application: Utility interconnection application number
• partner_system_id: Partner's internal project tracking ID
• legacy_project_id: Previous system project identifier for migrations

Response Information:

• Complete list of all external identifiers for the project
• Key-value pairs showing external system mappings
• Creation source and timestamps for audit trails
• Reference IDs for API operations

Integration Patterns:

• Data Synchronization: Use external IDs to sync project data across systems
• Webhook Processing: Match incoming webhook data using external identifiers
• Migration Support: Maintain references to legacy system identifiers
• Partner Integration: Enable partners to reference their own project IDs
• Cross-system Lookup: Find Elios projects using external system identifiers

Use Cases:

• Sync project status updates from partner systems
• Match utility interconnection applications with projects
• Maintain cross-references during data migrations
• Enable partner platforms to reference Elios projects
• Link with design tools and equipment procurement systems