fix(code): harden decision-table gates

[shafty023]

Purpose

Harden the canonical code decision-table skill after a workflow could continue despite Final Alignment Status: Not aligned and could miss mixed-source or executable-twin divergence.

Closes https://app.closedloop.ai/closedloop-ai/issues/ISS-5965

Changes

• Treat Not aligned as a terminal stop before PR creation, merge, completion, or success closeout; require the blocker, next action, and owner.
• Require bounded pairwise and high-risk coexistence/precedence cases when multiple evidence, authority, history, cache, or fallback sources can coexist.
• Require one shared scenario corpus through every real production boundary for helper, SQL, route, worker, producer, batch, and recovery twins.
• Make source-string, AST-presence, and SQL-shape assertions supplemental, and flag negative shape assertions that pin missing policy.
• Add stable row IDs and a Required Tests traceability table with wrong-input and mixed-state negative cases.
• Bump the code plugin to v1.14.8 and generate its changelog entry.

Affected files

• plugins/code/skills/decision-table/SKILL.md
• plugins/code/skills/decision-table/references/artifact-format.md
• plugins/code/skills/decision-table/references/edge-cases.md
• plugins/code/skills/decision-table/references/review-prevention.md
• plugins/code/tools/python/test_decision_table_skill_contract.py
• plugins/code/.claude-plugin/plugin.json
• CHANGELOG.md

Validation

• uv run pytest plugins/code/tools/python/ — 521 passed
• uv run ruff check .
• uv run pyright
• python3 plugins/platform/skills/claude-creator/scripts/quick_validate.py plugins/code/skills/decision-table
• git diff --check

Risk

Prompt-only workflow behavior change. Focused contract tests pin the new hard-stop, interaction, parity, and traceability guarantees.