ask: serialize concurrent CLI with repo lock and stale PID recovery

Add advisory lock under .git/hexai-ask.lock around Taskwarrior execution,
with metadata (PID and process basename) and Linux /proc comm checks to
remove orphan lock files when the recorded holder is gone or not ask.

Extract internal/filelock for shared flock helpers; stats uses it too.

Made-with: Cursor

1 files changed, 0 insertions, 24 deletions

diff --git a/internal/stats/lock_windows.go b/internal/stats/lock_windows.go
deleted file mode 100644
index 2ec5e90..0000000
--- a/internal/stats/lock_windows.go
+++ /dev/null
@@ -1,24 +0,0 @@
-//go:build windows
-
-package stats
-
-import (
-	"golang.org/x/sys/windows"
-)
-
-func tryLockFile(fd uintptr) error {
-	var ol windows.Overlapped
-	err := windows.LockFileEx(windows.Handle(fd), windows.LOCKFILE_EXCLUSIVE_LOCK|windows.LOCKFILE_FAIL_IMMEDIATELY, 0, 1, 0, &ol)
-	if err == nil {
-		return nil
-	}
-	if err == windows.ERROR_LOCK_VIOLATION {
-		return errLockWouldBlock
-	}
-	return err
-}
-
-func unlockFile(fd uintptr) error {
-	var ol windows.Overlapped
-	return windows.UnlockFileEx(windows.Handle(fd), 0, 1, 0, &ol)
-}