fix(alerts): explain raw-SQL sample counts and warn when they count rows - #1205

🟢 Confidence 5/5 · safe to merge
rawAlertSqlSelectsSamples now matches the engine's exact samples key, and the two new test files exercise both warning states.
_{quality 100/100 · no findings · tests covered · risk low}

Documents what minimum_sample_count counts for raw-SQL rules and adds rawAlertSampleCountWarning, surfaced in the alert editor and as warnings/notices on create, update and get. No evaluation behavior changes; safe to merge.

• rawAlertSampleCountWarning flags a raw-SQL rule whose minimum exceeds 1 with no samples column
• ruleConfigWarnings feeds warnings on create/update outputs and notices in renderRuleWrite
• Editor shows the warning and a raw-SQL samples/no-rows hint
• create_alert_rule parameter descriptions now state the real defaults (2/2/30)

Fixed since the last review

• ✅ F1 · rawAlertSqlSelectsSamples accepts Samples, which the engine never reads

_{ff972f2 · Updated on every push. Reply "won't fix" to dismiss a finding, or mention @maple-review-bot to ask about one.}