Add request-bound SOXL error 321 classifier

[Pigbibi]

Summary

• add provider-library-agnostic exact request-ID correlation for code 321
• persist only closed cause/code/commitments/completion aggregates via exclusive mode-0600 writer
• add offline synthetic coverage for correlation, precedence, redaction, frozen request fields, and accepted end-time representations

Validation

• UESP focused: 18 passed
• UESP full: 709 passed, 3 skipped
• QPK focused: 17 passed, 10 subtests passed
• Ruff, actionlint, compileall, dependency-enabled install/pip check, uv lock check, wheel build, scope/secret/privacy scans: passed

Safety

• no provider/API/credential/bars/acquisition calls
• no request-field, dependency, lock, runtime, cloud, deploy, paper/live, order, or capital changes

[chatgpt-codex-connector]

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