feat: validate rule file syntax conventions

[rhuanbarreto]

Summary

• Adds a syntax convention check to the rule loader that blocks .rules.ts files missing the /// <reference path="../rules.d.ts" /> directive or the satisfies RuleSet type assertion
• Reports these as blocked violations during archgate check with actionable error messages pointing to the exact location
• Updates blockedToRuleResult to distinguish syntax-check vs security-scan rule IDs
• Updates all test files to include the required syntax conventions

Test plan

• bun run validate passes (lint, typecheck, format, 586 tests, 22 ADR checks, build)
• Verify a rule file missing the triple-slash reference is reported as blocked
• Verify a rule file missing satisfies RuleSet is reported as blocked
• Verify a rule file missing both conventions reports 2 violations
• Verify existing valid rule files continue to load and execute normally