fix: increase timeout and retry settings for transport configuration

[shackmann]

Note

Low Risk
Behavior change only for callers relying on implicit transport defaults; no auth or wire-contract changes, but predictions may block longer before failing.

Overview
Raises the SDK’s default HTTP transport settings so hosted and local JointFM calls tolerate slower inference and more transient failures without custom YAML.

Timeouts go from 5s / 60s to 10s connect and 120s read. Retries go from 5 attempts with 1s backoff to 10 attempts with 2s initial backoff (max_backoff_seconds and retry status codes are unchanged).

Defaults are updated in TimeoutConfig / RetryConfig, mirrored in config.sample.yaml and the README example, and reflected in test_load_configuration_layers_yaml_over_defaults for fields not overridden in partial YAML.

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