fix: defer module-level side effects to prevent Bun 1.3.5 + macOS 15 segfault (#301)

- Remove eager SG_CLI_PATH constant; use getSgCliPath() lazily in checkEnvironment()
- Move setInterval to inside createCommentCheckerHooks() with guard flag

These changes eliminate module-level side effects that could trigger segfaults
during plugin initialization on Bun 1.3.5 + macOS 15 due to createRequire()
being called during module evaluation.

Fixes #292

Co-authored-by: sisyphus-dev-ai <sisyphus-dev-ai@users.noreply.github.com>

src/hooks/comment-checker/index.ts

@@ -21,6 +21,7 @@ const pendingCalls = new Map<string, PendingCall>()
 const PENDING_CALL_TTL = 60_000
 
 let cliPathPromise: Promise<string | null> | null = null
+let cleanupIntervalStarted = false
 
 function cleanupOldPendingCalls(): void {
   const now = Date.now()
@@ -31,10 +32,13 @@ function cleanupOldPendingCalls(): void {
   }
 }
 
-setInterval(cleanupOldPendingCalls, 10_000)
-
 export function createCommentCheckerHooks(config?: CommentCheckerConfig) {
   debugLog("createCommentCheckerHooks called", { config })
+
+  if (!cleanupIntervalStarted) {
+    cleanupIntervalStarted = true
+    setInterval(cleanupOldPendingCalls, 10_000)
+  }
   
   // Start background CLI initialization (may trigger lazy download)
   startBackgroundInit()