Break import cycle in domain persistent-damage modules

Extract persistent damage types and definitions into a leaf module so
events.ts and types.ts no longer import back into persistent-damage.ts.
Enable oxlint import/no-cycle (whole workspace via root tsconfig) to
keep cycles out.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

.oxlintrc.json

@@ -1,6 +1,6 @@
 {
 	"$schema": "https://raw.githubusercontent.com/nicolo-ribaudo/tc39-proposal-type-annotations/refs/heads/main/packages/oxlint/configuration_file_schema.json",
-	"plugins": ["typescript", "unicorn", "jest"],
+	"plugins": ["typescript", "unicorn", "jest", "import"],
 	"categories": {},
 	"rules": {
 		"typescript/no-unnecessary-type-assertion": "error",
@@ -8,6 +8,7 @@
 		"typescript/prefer-regexp-exec": "error",
 		"unicorn/prefer-string-replace-all": "error",
 		"unicorn/prefer-string-raw": "error",
+		"import/no-cycle": "error",
 		"jest/expect-expect": [
 			"error",
 			{