Fix Hang in Python 3.14 GH Actions (westpa#544)

* prevent inplace resize of arrays due to future numpy deprecation since 2.4.0
* use numpy.pad instead to ensure value is added in one step

Author: jeremyleung521

src/westpa/work_managers/zeromq/core.py

@@ -211,16 +211,10 @@ def add_timer(self, identifier, duration):
 
         new_idx = len(self._identifiers)
 
-        # Necessary due to coverage.py's use of a tracer triggering an error on resize
-        refcheck = True if sys.gettrace() is None else False
+        self._durations = np.pad(self._durations, (0, 1), mode='constant', constant_values=duration)
+        self._started = np.pad(self._started, (0, 1), mode='constant', constant_values=time.time())
+        self._identifiers = np.pad(self._identifiers, (0, 1), mode='constant', constant_values=identifier)
 
-        self._durations.resize((new_idx + 1,), refcheck=refcheck)
-        self._started.resize((new_idx + 1,), refcheck=refcheck)
-        self._identifiers.resize((new_idx + 1,), refcheck=refcheck)
-
-        self._durations[new_idx] = duration
-        self._started[new_idx] = time.time()
-        self._identifiers[new_idx] = identifier
         self._indices[identifier] = new_idx
 
     def remove_timer(self, identifier):