v2.67.0: ISO 26262 TCL3 coverage gate and compliance artifacts.

ISO 26262 TCL3 coverage gate and compliance artifacts.

Taint engine reaches 85.29% statement coverage. The gate is enforced at
fail_under = 85 in pyproject.toml so a regression in taint logic fails
the test suite before it reaches a firmware engagement.

New:

• tests/test_taint_labeled_coverage.py: 73 targeted tests covering
  TaintState.join() lattice paths, invalidate_base(), ARC atomic
  instructions, x86 _const instructions, MIPS/PPC FP handlers, and
  record_trace=True paths across all 6 qualified taint engine modules.
• docs/ABLATION-STANDARDS.md: compliance matrix v1.3.0 — 29 MET, 0 PARTIAL,
  against NIST SP 800-218 (SSDF), CISA Secure by Design, ISO 26262 TCL3,
  MIL-HDBK-115C, and DoWI 8430.01.
• docs/safety-manual.md: ISO 26262 Part 8 Clause 11 safety manual.
• docs/known-anomalies/: 16 known-anomaly files, one per taint tracker.
• docs/sbom/ablation-sbom.json: software bill of materials (pip-licenses).
• requirements-hashed.txt: hash-pinned dependency lockfile (pip-compile).
• scripts/monitor-supply-chain.sh: weekly pip-audit CVE scan.
• scripts/verify-account.sh: pre-push account verification gate.
• tests/conformance/: 43 ABI conformance tests for RH850 and TriCore.
• README compliance badges: NIST SP 800-218, CISA Secure by Design,
  MIL-HDBK-115C.
• SECURITY.md: Security Practices section documenting all controls.

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