IAV-841/refactor(agent): Simplify wizard step naming and add completion tracking

Summary

This MR refactors the agent wizard step naming convention and introduces wizard completion tracking for CustomerCare agents.

Changes

Refactoring

• Enum rename: MainAgentWizardStep → AgentWizardStep
  • Removes the "Main" prefix for cleaner, more generic naming that applies to all agent types
• Field rename: mainAgentWizardCurrentStep → agentWizardCurrentStep
  • Aligns with the new enum naming convention

New Features

• Wizard completion flag: Added wizardCompleted boolean field to CustomerCareAgent
  • Default value: false
  • Allows tracking whether an agent has completed the setup wizard

Bug Fixes

• Builder default for active field: Added @Builder.Default annotation to active field in Agent entity
  • Ensures active defaults to false when using Lombok builder pattern
  • Prevents potential NPE or unexpected behavior

Database Migration Required

⚠️ Yes - The following changes require a database migration:

• Rename column main_agent_wizard_current_step → agent_wizard_current_step
• Add new column wizard_completed (BOOLEAN, DEFAULT FALSE, NOT NULL)

Testing

• Unit tests updated for renamed enum
• Integration tests pass with new field
• Manual testing of wizard flow

Related Issues

• Closes IAV-841