[compiler-threat-spec] docs: sync CTR-025 framework self-prompt misattribution spec

[Copilot]

This PR closes a spec/implementation drift: CTR-025 behavior (framework <system> block stripping in threat-detection setup) was implemented and tested but not documented in the threat spec/compliance mapping.
It updates the threat-detection specification and conformance map so the normative catalog, implementation mapping, and test IDs align.

• Spec sync (v1.0.23)

  • Bumped specs/compiler-threat-detection-spec.md to 1.0.23.
  • Added Section 2 sync-table entry (1.0.23 → minimum binary v0.87.1, runtime-only behavior, no .lock.yml schema change).
  • Added changelog entry for 1.0.23 (2026-08-16).

• Rule + mapping coverage

  • Added CTR-025 Framework Self-Prompt Misattribution to Section 5.1.
  • Added Section 7.1 implementation mapping to:
    • actions/setup/js/setup_threat_detection.cjs (stripFrameworkSystemBlock, SYSTEM_BLOCK_REMOVED_MARKER)
    • actions/setup/js/setup_threat_detection.test.cjs

• Conformance ID alignment

  • Added T-CTR-039 in Section 8.1 for CTR-025.
  • Updated specs/compiler-threat-detection-compliance/README.md with CTR-025 → T-CTR-039.

• Release note entry

  • Added .changeset/sync-ctr-025-system-block-spec.md (patch) to record the documentation sync.

// Documented behavior for CTR-025:
const strippedPrompt = stripFrameworkSystemBlock(rawPrompt);
// strips only leading framework <system>...</system> block
// preserves later <system> lookalikes for threat analysis

• Fixes [compiler-threat-spec] docs: sync CTR-025 framework self-prompt misattribution spec #53016

[Copilot]

Pull request overview

Documents the existing CTR-025 framework prompt-stripping behavior and aligns its conformance mapping.

Changes:

• Adds CTR-025 and T-CTR-039 to specification version 1.0.23.
• Maps the rule to its implementation and tests.
• Adds compliance and release-note entries.

Show a summary per file

File	Description
specs/compiler-threat-detection-spec.md	Adds the normative rule, mappings, test ID, and changelog.
specs/compiler-threat-detection-compliance/README.md	Maps CTR-025 to T-CTR-039.
.changeset/sync-ctr-025-system-block-spec.md	Records the documentation patch.

Review details

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Suppressed comments (1)

specs/compiler-threat-detection-spec.md:423

• The changelog repeats the incorrect v0.87.1 minimum. Since the CTR-025 implementation is already present in v0.87.0, keep this entry aligned with the corrected sync-table version.

- Updated Section 2 spec-to-implementation sync table with version 1.0.23 mapped to minimum binary `v0.87.1` and no `.lock.yml` schema changes.

• Files reviewed: 3/3 changed files
• Comments generated: 1
• Review effort level: Balanced

[github-actions]

🎉 This pull request is included in a new release.

Release: v0.87.1