[2026 Security] Redact secrets and signed XDR from diagnostics

[Nanle-code]

Objective

Prevent secret keys, tokens, signed envelopes, and sensitive memos from reaching telemetry.

Target area

error reporting, logs, and analytics

Acceptance criteria

• The objective is implemented with clear handling for invalid input, unsupported environments, and failure paths.
• Automated tests cover the primary flow, at least one boundary case, and at least one failure case.
• User-facing documentation or developer guidance is updated, including compatibility, security, or migration notes where applicable.

Source: .github/roadmap-issues-2026-07-29.json.