Repair live qualification after regression audit

[KeyffMS]

Summary

Implements the 2026-09-03 regression audit before another self-hosted qualification run.

Audit-driven repairs

• consolidate C03/C06/C08/C09/C13/C16 under the existing v6 entrypoint; no v7 wrapper;
• move hook telemetry for read-only C08/C09/C13 to an external writable sidecar and make recorder I/O fail-open so telemetry cannot alter real hook semantics;
• lower and reinforce C08/C09 body-after-prefix auto-compaction triggers only after fixing hook instrumentation;
• replace C03 generic planner/evaluator dependence with an explicit auxiliary writable Git source, real PlanAnvil bootstrap, source invariants, and deterministic topology/config validation;
• add an independent minimal ^apply_patch$ PreToolUse repro to C06 so a current-runtime hook discrepancy cannot be hidden as a harness fix;
• preserve the baseline-2.3 C13 ephemeral-first/known-error fallback while repairing its telemetry path;
• replace C16 evaluator dependence with deterministic outer classification/diagnostic/cleanup checks plus matching live Codex trials.

Regression audit

docs/CODEX_QUALIFICATION_REGRESSION_AUDIT_2026-09-03.md records run #9 root causes, previously reproduced capability review, repair invariants, and the exit gate before another full qualification.

Safety

• workflow remains workflow_dispatch only from main;
• no self-hosted qualification runs on this PR;
• approval remains never, model-tool network remains disabled;
• no sandbox/approval bypass, privileged container, SYS_ADMIN, or danger-full-access change;
• baseline 2.3 remains unchanged.

A new full qualification must not be dispatched until this PR and post-merge hosted CI are fully green.