fix(core): eliminate status/connections file race conditions on macOS (closes #535)

[s2x]

Description

Closes #535

WorkermanCommandTest fails on macOS because of a race condition in status/connections file reading. Workerman's SIGIOT handler truncates the status file to 0 bytes before writing content. PHP's stat cache combined with stale status files from interrupted runs causes waitForFile() to detect the file before content is written, returning empty or partial data.

Changes

• StatusFileReader::waitForFile(): Call clearstatcache() before each poll to avoid cached stale stats. Reject 0-byte files (written during the SIGIOT handler's truncate phase).

• ServerManager::getStatus() / getConnections(): Delete the stale status/connections file @unlink() before sending SIGIOT/SIGIO, so waitForFile() always waits for fresh output from the current signal.

• StatusFileReaderTest: Write content to the temp file in testWaitForFileReturnsTrueWhenFileExists (previously empty). Add testWaitForFileReturnsFalseWhenFileEmpty to cover the 0-byte rejection path.

Changelog

Fix race condition in ServerManager::getStatus() / getConnections() where PHP's stat cache and stale status files could cause waitForFile() to read an empty or incomplete file. StatusFileReader::waitForFile() now clears the stat cache per poll and rejects 0-byte files. ServerManager deletes the stale file before signaling, ensuring fresh output is waited for.

Code Review

• Passed subagent code review
• All review comments addressed