feat: add directory-scoped host defaults (match_dirs) and repo list --limit

Add match_dirs field to host config entries for directory-based host
resolution. When no --hostname flag, FGJ_HOST env var, or git remote is
detected, the longest matching directory prefix determines the host.
Symlinks are resolved on both sides for macOS compatibility (/tmp →
/private/tmp). Also adds --limit/-L flag to repo list.

cmd/root.go

@@ -96,6 +96,15 @@ func getDetectedHost() string {
 	return host
 }
 
+// getCwd returns the current working directory, or "" on error.
+func getCwd() string {
+	cwd, err := os.Getwd()
+	if err != nil {
+		return ""
+	}
+	return cwd
+}
+
 // promptLine prints a prompt to stderr and reads a line from stdin.
 func promptLine(prompt string) (string, error) {
 	fmt.Fprint(ios.ErrOut, prompt)