feat(seatbelt): add handle_unavailable to RetryConfig and HedgingConfig

[martintmk]

Add the handle_unavailable boolean field to both config structs so it can be driven from external configuration sources (e.g. config files). The field defaults to false, matching the existing layer default.

The config() methods on RetryLayer and HedgingLayer now forward the new field, and all snapshot tests are updated accordingly.

[Copilot]

Pull request overview

Adds a handle_unavailable: bool flag to both retry and hedging configuration structs so the existing layer behavior can be controlled via externally loaded config (e.g., JSON), and wires those configs through the respective Layer::config() convenience methods.

Changes:

• Add handle_unavailable to RetryConfig and HedgingConfig with a default of false.
• Forward handle_unavailable through RetryLayer::config() and HedgingLayer::config().
• Update relevant insta snapshots to reflect the new field.

Reviewed changes

Copilot reviewed 12 out of 13 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
crates/seatbelt/src/retry/config.rs	Adds handle_unavailable to RetryConfig and documents its default/meaning.
crates/seatbelt/src/retry/layer.rs	Forwards handle_unavailable from RetryConfig via .config().
crates/seatbelt/src/retry/snapshots/seatbelt__retry__config__tests__default_snapshot.snap	Updates JSON snapshot to include handle_unavailable.
crates/seatbelt/src/retry/snapshots/seatbelt__retry__layer__tests__config_applies_all_settings.snap	Updates debug snapshot for config_applies_all_settings.
crates/seatbelt/src/hedging/config.rs	Adds handle_unavailable to HedgingConfig and documents its default/meaning.
crates/seatbelt/src/hedging/layer.rs	Forwards handle_unavailable from HedgingConfig via .config().
crates/seatbelt/src/hedging/snapshots/seatbelt__hedging__config__tests__default_snapshot.snap	Updates JSON snapshot to include handle_unavailable.
crates/seatbelt/src/hedging/snapshots/seatbelt__hedging__layer__tests__config_applies_all_settings.snap	Updates debug snapshot for config_applies_all_settings.

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 100.0%. Comparing base (d60d207) to head (d03c4c7).

Additional details and impacted files

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##             main     #314   +/-   ##
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  Coverage   100.0%   100.0%           
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  Files         153      153           
  Lines        9401     9405    +4     
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+ Hits         9401     9405    +4     

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[Copilot]

Pull request overview

Copilot reviewed 13 out of 14 changed files in this pull request and generated no new comments.

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