[Bug]: two commits created in one transaction fail the monotonic-commit trigger #413

What type of issue is this?

• Bug report
• Feature request

Prerequisites

• I have written a descriptive issue title
• I have verified that I am running the latest version of the SysML2.NET
• I have searched open and closed issues to ensure it has not already been reported

Description

commit.created defaults to now() (schema.generated.sql:297), which returns the transaction start time. Two commits created in one transaction get identical timestamps, and trg_commit_parent_monotonic (:354-379) rejects the parent edge between them as not strictly newer.

SysML2.NET.CodeGenerator.Tests/Sql/schema.concurrency.setup.sql:20 already stamps commits with clock_timestamp() for this reason; the schema default contradicts it, and any insert that omits created hits the problem.

Expected: a parent and child commit created in one transaction get distinct, increasing timestamps.

Fix:

• Change the default to clock_timestamp(), or drop the default so the service must supply created.
• Add the case to schema.smoke.sql.

Steps to Reproduce

BEGIN;
INSERT INTO sysml2.commit (id, project_id, model_version_id) VALUES (:c1, :p, 1), (:c2, :p, 1);
INSERT INTO sysml2.commit_parent (commit_id, parent_commit_id, ordinal) VALUES (:c2, :c1, 0);
-- ERROR: commit … is not strictly newer than its parent …

System Configuration

• SysML2.NET version: PR [ADD] Sql schema #344 (feat/sql-schema-and-more, d5a90f2), SysML2.NET.CodeGenerator
• Environment (Operating system, version and so on): Windows 11, PostgreSQL 17 (Docker)
• .NET Framework version: .NET 10
• Additional information: none