[Feature]: Provide a config array to configure fallback retry modells when using openrouter

[rufreakde]

1. Why Do You NEED This Feature?

when using models like:

• qwen/qwen3.6-plus:free
• nvidia/nemotron-3-super-120b-a12b:free
• qwen/qwen3-coder:free

it would be nice to not only be able to configure retry mechanisms to cope with times of huge usages

2. What Is NOT Possible Right Now?

currently:

[retry]
# Backoff multiplication factor for each retry attempt
backoff_factor = 2

# Initial backoff delay in milliseconds for retry operations
initial_backoff_ms = 200

# Maximum number of retry attempts
max_attempts = 8

# Minimum delay in milliseconds between retry attempts
min_delay_ms = 1000

# HTTP status codes that should trigger retries
status_codes = [429, 500, 502, 503, 504, 408, 522, 520, 529]

# Whether to suppress retry error logging and events
suppress_errors = false

desired additionally:

fallback_model_after_max_attempts = true
fallback_models = [ qwen/qwen3.6-plus:free, qwen/qwen3-coder:free ]

3. What WILL Be Possible With This Feature?

Allowing the model to be switched easily during an unsupervised run when developer is afk for a longer period of time and somehow the model failed!

Proposed Solution (User Experience)

• improvement for user experience with configurable automatic handling
• unsupervised working without potential time loss!

Alternatives Considered

No response

Feature Category

Configuration

Priority/Impact

High - Would significantly improve my workflow

Examples from Other Tools

No response

Additional Context

No response

Pre-submission Checklist

• I have searched existing issues and confirmed this is not a duplicate
• I am willing to submit a PR to implement this feature