v1.12.0

• --explain flag — plain-language explanations and remediation hints per finding on borderlint scan: the text report gains one → line per reason stating which provider resolves where, why that is disallowed for the data class, and what to change; the JSON report gains an explanation field per finding (absent without the flag, so existing consumers see no schema change). Deterministic template-driven text, no LLM in the loop; advisory only — exit codes and gating semantics untouched.
• Claude plugin — version field in plugin.json so claude plugin validate --strict passes clean.
• KB drift report — stamped with the run date for a visible weekly heartbeat.