fix: address code review feedback (batch 2)

1. Add logger to writeCacheFile (version-cache.ts)
   - Now logs warnings when file write fails
   - Helps debugging in production environments

2. Sanitize logging in parseGroupResult (communities.ts)
   - Changed from info to debug level
   - Removed full node/groupNode dumps (sensitive data)
   - Now only logs nodeTag and groupId

3. Add input validation in parseNewsletterCreateResponse (newsletter.ts)
   - Validates response structure before destructuring
   - Adds fallback values for parseInt (prevents NaN)
   - Adds null checks for optional fields

4. Add health-status.ts module
   - getHealthStatus(): Full health check with circuit breakers, cache, memory
   - isHealthy(): Simple boolean for liveness probes
   - getSimpleHealthStatus(): Returns 'ok', 'degraded', or 'error'
   - Useful for k8s probes and monitoring dashboards

src/Utils/version-cache.ts

@@ -86,11 +86,16 @@ async function readCacheFile(filePath: string): Promise<VersionCacheEntry | null
 /**
  * Writes the cache to file
  */
-async function writeCacheFile(filePath: string, entry: VersionCacheEntry): Promise<void> {
+async function writeCacheFile(
+	filePath: string,
+	entry: VersionCacheEntry,
+	logger?: VersionCacheLogger
+): Promise<void> {
 	try {
 		await fs.writeFile(filePath, JSON.stringify(entry, null, 2), 'utf-8')
-	} catch {
-		// Ignore write errors - cache is optional
+	} catch (error) {
+		// Log write errors for debugging - cache is optional but failures should be visible
+		logger?.warn({ error, filePath }, 'Failed to write version cache file')
 	}
 }
 
@@ -124,7 +129,7 @@ async function fetchVersionOnce(
 	memoryCache = entry
 
 	// Persist to file (async, don't wait)
-	writeCacheFile(cacheFilePath, entry).catch(() => {})
+	writeCacheFile(cacheFilePath, entry, logger).catch(() => {})
 
 	logger?.info(
 		{ version: entry.version, source: entry.source },