v1.5.1 — eight more craftsman rules

Skill additions, all woven into the existing loop:

• One line? One line. And between two equal-size options, take the one that's correct on edge cases — less code never means a flimsier algorithm.
• Deletion over addition, boring over clever, and prefer editing an existing file over creating a new one.
• User insists on the full version? Build it — no re-arguing.
• YAGNI applies to tests too: one minimal check, no frameworks or per-function suites unless asked.
• 'skipped X — add when Y' one-line reporting convention for deliberate omissions.
• Requested explanation is never debt — brevity rules bind only unrequested prose.

AGENTS.md regenerated to match.