Register the human decision migration as readable by old binaries

Why: The new confirmation table is additive, and the compatibility ledger must name that fact or the store suite rejects the schema.

Evidence: SELF go test ./internal/store/ -run TestMigrationCompatRegistered passed after the registration.

Impact: Old readers keep their current floor. They do not need to understand human decision rows.

Refs: W4b human confirmation design r1
Co-authored-by: Cursor <cursoragent@cursor.com>

internal/store/migrate_compat.go

@@ -49,6 +49,7 @@ var migrationBreaksOldReaders = map[int]bool{
 	42: false, // project_audit_committed_prefix：PG 审计 ID 默认函数，旧读者兼容
 	43: false, // project_audit_all_writers_guard：PG 在线审计写入门禁，旧读者兼容
 	44: false, // project_work_observation_outbox：独立私域投递表，旧读者不读取
+	45: false, // human_decision_proofs：独立真人确认表，旧读者不读取
 }
 
 // SchemaTarget 是本二进制会迁移到的 schema 版本。