[FEATURE] Support per-phase model and reasoning configuration in Mastra Factory

Problem Statement

I would like to use different models and reasoning levels for each stage in Mastra Factory.

The current documentation describes selecting a default model for tasks on a Factory’s boards.

Proposed Solution

Support optional model and reasoning overrides at the phase level.

For example:

Planning → GPT Astra, high reasoning Building → GPT Luna, Max reasoning Review → GPT Astra, high reasoning

Component

Other

Alternatives Considered

No response

Example Use Case

When an issue enters Planning, GPT Astra would investigate the issue and produce the implementation plan.

When the plan is approved, GPT Luna with Max reasoning would implement the changes.

When implementation is complete, GPT Astra would independently review the code and report issues before the work is marked Done.

Additional Context

No response

Verification

• I have searched the existing issues to make sure this is not a duplicate
• I have provided sufficient context for the team to understand the request