test: debug Phala attestation tcb_info_issuer_chain parsing failure

[barakeinav1]

DO NOT MERGE — debugging only

Temporary debug changes to investigate the tcb_info_issuer_chain parsing error when uploading TDX quotes to Phala's attestation service.

Changes

• Dump raw Phala response before parsing (length, first/last 500 chars)
• Show response context around the error column on parse failure
• Fall back to Mock attestation instead of crashing (so the node stays alive for further debugging)

Background

All MPC nodes fail Dstack attestation with:

Missing or invalid field: tcb_info_issuer_chain at line 1 column 5620

See mpc-private#261 for full investigation.

To test

Build and push the MPC node image from this branch, deploy in a TEE CVM, check logs.

[claude]

PR title type suggestion: This PR modifies source code and dependencies, not test files. Since it's addressing a parsing failure, the type prefix should probably be fix: instead of test:.

Suggested title: fix: debug Phala attestation tcb_info_issuer_chain parsing failure

[claude]

Review: test/debug Phala attestation

PR is marked DO NOT MERGE — reviewing for issues that could cause harm if accidentally merged or if the debug branch runs longer than expected.

⚠️ Critical: Mock attestation fallback bypasses TEE security

crates/node/src/run.rs:90-99 — On attestation failure, the node silently falls back to MockAttestation::Valid. If this code reaches any non-debug environment, it means a node can join the MPC network without a valid TEE attestation, completely undermining the trust model.

Even for a temporary debug branch deployed to a CVM, this is risky:

• If other nodes or the contract accept Mock attestations, this node would be operating without hardware-backed integrity guarantees.
• The error is logged, but nothing prevents the node from participating in signing.

Suggestion: If the goal is to keep the node alive for log inspection, consider failing after logging (i.e., still exit/crash) or gating the fallback behind an explicit --unsafe-allow-mock-attestation flag so it can't happen silently.

Minor: Response body may contain sensitive data in logs

crates/tee-authority/src/tee_authority.rs:153-163 — Dumping up to 1000 chars of the Phala response at info level. This is fine for a debug branch, but ensure these logs aren't shipped to any shared/persistent logging backend where the attestation service response could leak.

No other issues found. The debug logging and serde_json parse-then-report pattern are reasonable for the stated investigation purpose.

⚠️ Issues found — do not merge as-is (which aligns with the PR's own label).

[claude]

PR title type suggestion: This PR modifies source code files to fix a parsing failure, so the type prefix should probably be fix: instead of test:.

Suggested title: fix: handle Phala attestation tcb_info_issuer_chain parsing