Fix repeated risk-signal reviews after successful submission

[piaro]

Problem

Submitting a refreshed risk-signal review could succeed while the next action requested the same review again. Results are sorted by content-derived IDs, and an older non-applicability review could overwrite a current one solely because its ID sorted later.

Change

Select candidate reviews using current evidence before resolving ties, and share the selection across the kernel, explanations, and challenge context. Confirmation remains binding across evidence changes and takes precedence over conflicting non-applicability. Preserve independent challenge and reopen non-applicability when its evidence changes.

Update the CLI/MCP output schema descriptions, Analyst skill, and English and Japanese documentation.

Validation

• Added a seven-candidate regression that fails before the fix and passes afterward, including reversed Result order and subsequent evidence changes.
• Added conflicting-review coverage and a CLI/MCP integration test across process restarts.
• Passed cargo fmt --check, cargo clippy --all-targets --locked -- -D warnings, cargo test --locked, and sh scripts/tests/test-rust.sh.