Update foundational examples with script dependencies

examples/foundational/20a-persistent-context-openai.py

@@ -4,6 +4,12 @@
 # SPDX-License-Identifier: BSD 2-Clause License
 #
 
+# /// script
+# dependencies = [
+#   "pipecat-ai[daily,webrtc,websocket,runner,silero,deepgram,openai,cartesia]>=0.0.77",
+# ]
+# ///
+
 import glob
 import json
 import os
@@ -192,6 +198,8 @@ async def run_bot(transport: BaseTransport):
 
     global tts
 
+    stt = DeepgramSTTService(api_key=os.getenv("DEEPGRAM_API_KEY"))
+
     tts = CartesiaTTSService(
         api_key=os.getenv("CARTESIA_API_KEY"),
         voice_id="71a7ad14-091c-4e8e-a314-022ece01c121",  # British Reading Lady