feat: Replace portfolio/position ops with unified portfolio block management

[jfrench9]

Summary

Introduces a new portfolio block abstraction that unifies portfolio and position operations into a single, cohesive management model. This replaces the previous separate CRUD operations for portfolios and positions with consolidated portfolio block operations that handle both concerns atomically.

Key Accomplishments

API Layer Refactoring

• Renamed and refactored op_create_portfolio, op_delete_portfolio, and op_update_portfolio to their _block counterparts (op_create_portfolio_block, op_delete_portfolio_block, op_update_portfolio_block)
• Removed standalone position operation modules (op_create_position, op_delete_position, op_update_position) — position management is now handled within portfolio block operations

New Domain Models

• CreatePortfolioBlockRequest — encapsulates portfolio creation with embedded position data
• UpdatePortfolioBlockOperation — supports portfolio patching, position adds, updates, and disposals in a single operation
• DeletePortfolioBlockOperation — handles portfolio block deletion
• PortfolioBlockPortfolioFields — defines portfolio-level field schema
• PortfolioBlockPortfolioPatch — represents partial portfolio updates
• PortfolioBlockPositionAdd / PortfolioBlockPositionUpdate / PortfolioBlockPositionDispose — granular position mutation types within a block context
• PortfolioBlockPositions — container model for position collections

Client Simplification

• Refactored investor_client.py to use the new portfolio block API surface, reducing overall complexity (~120 lines net reduction in client code)
• Updated GraphQL query definitions in the investor query module to align with the new block-based schema

Model Exports

• Updated models/__init__.py to export all new models and remove deprecated ones

Breaking Changes

⚠️ This is a breaking change for all consumers of the investor client API.

• Removed operations: create_portfolio, update_portfolio, delete_portfolio, create_position, update_position, delete_position — these no longer exist as separate client methods
• Removed models: CreatePortfolioRequest, UpdatePortfolioOperation, DeletePortfolioOperation, CreatePositionRequest, UpdatePositionOperation, DeletePositionOperation
• Replaced by: Portfolio block equivalents (create_portfolio_block, update_portfolio_block, delete_portfolio_block) which manage positions inline
• Consumers must migrate to the new portfolio block API and update all model imports accordingly

Testing

• tests/test_investor_client.py has been substantially updated (~175 lines changed) to cover the new portfolio block operations
• Tests cover creation, update (including position add/update/dispose), and deletion flows
• Existing position-specific test cases have been replaced with block-level equivalents

Infrastructure Considerations

• GraphQL schema/queries have been updated to support the new block-based operations — ensure the backend GraphQL API is deployed with the corresponding schema changes before rolling out this client version
• No new dependencies introduced; net reduction in codebase size (~310 fewer lines overall)

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🤖 Generated with Claude Code

Branch Info:

• Source: feature/portfolio-block
• Target: main
• Type: feature

Co-Authored-By: Claude noreply@anthropic.com