sub2api/openspec/changes/image-stream-resilience/tasks.md

1. Config and defaults

• 1.1 Add image-specific stream timeout fields to gateway config.
• 1.2 Register image stream timeout defaults in the config loader.
• 1.3 Add config validation for image stream timeout ranges.
• 1.4 Expose image stream timeout defaults in deploy/config.example.yaml.

2. Image stream runtime behavior

• 2.1 Detach image stream upstream contexts from client cancellation.
• 2.2 Add image-specific data interval timeout handling to /v1/images/* streaming.
• 2.3 Add image-specific data interval timeout handling to Responses + image_generation streaming.
• 2.4 Preserve upstream draining after downstream write failures in both image stream paths.

3. Tests and verification

• 3.1 Add config tests for image stream timeout defaults and validation.
• 3.2 Add image streaming disconnect tests for the Images API path.
• 3.3 Add image streaming disconnect tests for the Responses image tool path.
• 3.4 Run focused Go tests for the touched config and image service paths.