Bound upstream provider response memory

[AnthonyRonning]

Summary

• replace unbounded provider-body collection with a checked aggregate reader
• apply response-class-specific ceilings: 16 MiB completion JSON, 4 MiB model metadata, 64 MiB embeddings, 32 MiB transcription JSON, 100 MiB TTS audio, and 64 KiB diagnostic error bodies
• cap each unfinished SSE frame at 1 MiB while incrementally draining coalesced frames and retaining the existing 120-second per-chunk timeout
• keep public request APIs, routing, SSE grammar, and tool-call handling unchanged
• add deterministic boundary, overflow, delimiter-free accumulation, split-frame, and coalesced-frame tests

Validation

• nix develop -c cargo fmt --all -- --check
• git diff --check
• nix develop -c cargo test web::openai::tests::provider_body_limit -- --nocapture (2 passed)
• nix develop -c cargo test web::openai::tests::sse_ -- --nocapture (4 passed)
• nix develop -c cargo clippy --all-targets --all-features -- -D warnings
• nix develop -c cargo test --all-features (219 passed, 16 database-dependent tests ignored)

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Review details

⚙️ Run configuration

Configuration used: Repository UI

Review profile: CHILL

Plan: Pro

Run ID: 61bea7ac-e080-48b2-b7e7-b0d5e257a99a

📥 Commits

Reviewing files that changed from the base of the PR and between a3ecc93 and 0ad34e6.

📒 Files selected for processing (2)

• src/web/health_routes.rs
• src/web/openai.rs

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch codex-opensecret-provider-response-bounds-opensecret

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[devin-ai-integration]

✅ Devin Review: No Issues Found

Devin Review analyzed this PR and found no bugs or issues to report.

[AnthonyRonning]

Amended this response-bounds PR to cover the remaining extended-health model fetch:

• streams successful model bodies through the shared 4 MiB aggregate limit
• bounds non-success bodies to 64 KiB and returns only a sanitized 150-character excerpt
• maps oversize/read/parse failures through the existing HTTP 503 health-check response
• adds four focused multi-chunk tests for accepted models, oversized models, oversized errors, and excerpt truncation

Validation: cargo fmt --check; git diff --check; cargo clippy --locked --all-targets --all-features with warnings denied; cargo test --locked (223 passed, 16 database-dependent tests ignored).