fix(parser): wrap parseAnthropicTokenLimitError in try/catch

Add outer try/catch to prevent crashes from non-standard error objects
returned by proxy providers (e.g., Antigravity). Add parser tests
covering edge cases: circular refs, non-object data fields, invalid
JSON in responseBody.

src/hooks/anthropic-context-window-limit-recovery/parser.ts

@@ -74,6 +74,14 @@ function isTokenLimitError(text: string): boolean {
 }
 
 export function parseAnthropicTokenLimitError(err: unknown): ParsedTokenLimitError | null {
+  try {
+    return parseAnthropicTokenLimitErrorUnsafe(err)
+  } catch {
+    return null
+  }
+}
+
+function parseAnthropicTokenLimitErrorUnsafe(err: unknown): ParsedTokenLimitError | null {
   if (typeof err === "string") {
     if (err.toLowerCase().includes("non-empty content")) {
       return {