fix: decode nested encodings symmetrically

[Ricky Gummadi (Ricky-G)]

Summary

Restore symmetric nested-encoding normalization in Python and Rust. Percent-, Unicode-escape-, and HTML-entity-wrapped base64/hex payloads now decode fully and emit both transform tags.

Fixes #3502 and #3521.

Problem

The ambiguous outer-layer guard required an English-marker gain. When decoding revealed another encoded blob, both sides scored zero, leaving the six reported nesting forms verbatim with no transform metadata. PR #3503 was closed unmerged, so the defect remains on main.

Changes

File	What changed
agent-governance-python/agent-os/src/agent_os/normalize.py	Reuse the base64/hex decoder to accept an outer decode only when the revealed blob actually produces printable UTF-8 text.
agent-governance-python/agent-os/tests/test_normalize.py	Cover both nesting orders for all six wrapper/blob pairs and reject a nested blob that decodes to nonprintable content.
agent-governance-rust/agentmesh/src/normalize.rs	Mirror the guard and regression coverage in Rust.

Testing

• python -m pytest agent-governance-python/agent-os/tests/test_normalize.py -q — 23 passed.
• cargo test --manifest-path agent-governance-rust/agentmesh/Cargo.toml normalize — passed.
• python -m ruff check --select E,F,W --ignore E501 ... — passed.
• rustfmt --edition 2021 --check agent-governance-rust/agentmesh/src/normalize.rs — passed.
• Crate-wide cargo fmt --check still reports a pre-existing formatting difference in agentmesh/src/prompt_injection_embedding.rs; the changed module is formatted.

[github-actions]

Dependency Review

✅ No vulnerabilities or license issues or OpenSSF Scorecard issues found.

Scanned Files

None

[github-actions]

PR Review Summary

Check	Status	Details
🔍 Code Review	⚠️ Missing	No current-run comment
🛡️ Security Scan	⚠️ Missing	No current-run comment
🔄 Breaking Changes	⚠️ Missing	No current-run comment
📝 Docs Sync	⚠️ Missing	No current-run comment
🧪 Test Coverage	⚠️ Missing	No current-run comment

Verdict: ⚠️ AI review incomplete; ready for human review

AI review comments are untrusted advisory output. The summary reports workflow-generated completion status only, not model-authored pass/fail claims.

[MohammadHaroonAbuomar]

• agent-governance-rust/agentmesh/src/normalize.rs:1 Both license-header checks fail because this file has lacked the two-line Microsoft MIT header since #2991 and the checks are diff-scoped; add the header and they go green.

[Ricky Gummadi (Ricky-G)]

Both license-header checks fail because this file has lacked the two-line Microsoft MIT header since #2991; add the header and they go green.

Added the requested copyright and license header to normalize.rs in 3fcf3241.

[MohammadHaroonAbuomar]

Approving at 3fcf324. The only changes since the verified 0cc316c are the license header on normalize.rs and the non_printable rename in both test names; both license-header checks and the spell check are green, and the fuzzing job still running is not required. The decoder change was verified in the previous round: all six wrapper-outside nesting forms decode with both tags in Python and Rust with no divergence, the printable-UTF-8 gate refuses binary and control-heavy payloads even when wrapped, ordinary text with percent escapes, entities, hex-looking words and JSON escapes is untouched, and the depth and ratio caps hold on large nested input.