[M5] MODE 1: Add workflow_application_id column (PostgreSQL)

[ricardozanini]

Add workflow_application_id column to MODE 1 PostgreSQL schema with trigger extraction.

Implementation:

• Database migration: ALTER TABLE workflow_instances ADD COLUMN workflow_application_id VARCHAR(255);
• Trigger update: Extract field from JSONB event data
• JPA entity: Add workflowApplicationId field to WorkflowInstanceEntity
• Mapper: Update WorkflowInstanceEntityMapper
• Domain model: Add field to WorkflowInstance
• GraphQL: Add field + filter to schema

Acceptance Criteria:

• Database column added via Flyway migration
• Trigger extracts field from events
• JPA entity includes field
• GraphQL schema includes field and filter
• Integration test queries by workflowApplicationId

Reference: ADR-0002 (Future Work: MODE 1 Implementation)

Part of: Epic kubesmarts/logic-operator#48