security(claude-review): AUT-2169 isolate analysis from publication

[svcnemo-autobot]

Background

Preserve Megatron-LM review behavior while separating read-only analysis from validated publication.

What changed

• Enforce exact light/strict commands and explicit reviewer authorization.
• Build bounded immutable BASE/MERGE_BASE/HEAD context from trusted base content.
• Separate schema-constrained analysis from deterministic OIDC claude[bot] publication.
• Replace approval with a non-approving LGTM comment.
• Harden CLI failure handling and split bounded context serving into its own trusted module.

Details

flowchart LR
  C[Authorized command] --> X[Immutable context]
  X --> A[Read-only analysis]
  A --> V[Deterministic validation]
  V --> P[claude bot COMMENT publication]

Loading

Analysis has no publication or OIDC permission. The publisher verifies trusted modules and validates revisions, coverage, findings, paths, sides, lines, and limits before COMMENT-only publication. Binary, symlink, submodule, special-file, and large-change handling fails closed.

Tested

• 50 focused parser, authorization, context, schema, safety, workflow-boundary, and publisher tests
• YAML parsing and targeted actionlint
• Ruff, Black 26.3.0, isort, and Python compilation
• CLI error-path and prohibited-reference scans
• git diff --check unavailable because the managed file-only checkout omits Git metadata; CI remains authoritative

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