docs: add coverage threshold marker to TEST_EVIDENCE.md

[Copilot]

scripts/check_coverage_policy.py validates that docs/TEST_EVIDENCE.md contains a **>= 95%** marker matching the --fail-under-lines threshold in scripts/test_evidence.sh. The marker was absent, causing CI to fail at the "Check coverage policy consistency" step.

Summary

Added **>= 95%** to docs/TEST_EVIDENCE.md under the "Evidence captured by these tests" heading to satisfy the policy consistency check.

## Evidence captured by these tests

**>= 95%**

### Protocol compatibility

Related references

• AGENTS.md
• TESTING_EVIDENCE.md
• docs/TEST_EVIDENCE.md
• docs/TEST_COVERAGE_MATRIX.md

Change type

• Bug fix
• Feature
• Refactor
• Docs only
• Test-only

Protocol and safety impact

• No protocol logic changes
• Determinism impact reviewed (ordering/hash/canonicalization)
• Panic risk reviewed on request/runtime paths
• Network-facing inputs validated fail-closed
• No secrets/raw payloads added to logs

Testing checklist

• Tests are black-box (public APIs/external behavior)
• Tests do not copy/paste production logic into assertions
• Numeric boundary cases are tested
• Deterministic functions/flows include determinism assertions
• cargo fmt --check passes
• cargo clippy --workspace --all-targets -- -D warnings passes
• cargo test --workspace passes
• No new unsafe code

Evidence

$ python3 scripts/check_coverage_policy.py
Coverage policy consistency check passed (threshold: 95%)

Original prompt

Problem

The CI job is failing at the "Check coverage policy consistency" step because docs/TEST_EVIDENCE.md is missing the required coverage threshold marker.

The script scripts/check_coverage_policy.py validates that docs/TEST_EVIDENCE.md contains a line matching the pattern **>= 95%** (where 95 is extracted from --fail-under-lines 95 in scripts/test_evidence.sh line 57).

Error from CI:

Coverage policy mismatch detected:
- docs/TEST_EVIDENCE.md: expected to match /\*\*>=\s*95%\*\*/

Solution Required

Add the coverage threshold marker **>= 95%** to docs/TEST_EVIDENCE.md.

A good location would be in a coverage section. Add it after the "Evidence captured by these tests" heading (after line 29), like:

## Evidence captured by these tests

**>= 95%**

### Protocol compatibility

This will satisfy the policy consistency check and allow the CI pipeline to proceed.

This pull request was created from Copilot chat.

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