Add explicit app.run() to the docs (#551)

Author: daniil-quix

docs/connectors/sinks/README.md

@@ -28,6 +28,9 @@ sdf = app.dataframe(topic)
 # Do some processing here ...
 # Sink data to InfluxDB
 sdf.sink(influx_sink)
+
+if __name__ == '__main__':
+    app.run()
 ```
 
 ## Sinks Are Terminal Operations
@@ -118,4 +121,7 @@ influx_sink = InfluxDB3Sink(
 
 # The sink will write to InfluxDB across all assigned partitions.
 sdf.sink(influx_sink)
+
+if __name__ == '__main__':
+    app.run()
 ```

docs/connectors/sinks/csv-sink.md

@@ -23,6 +23,9 @@ sdf = app.dataframe(topic)
 # Do some processing here ...
 # Sink data to a CSV file
 sdf.sink(csv_sink)
+
+if __name__ == '__main__':
+    app.run()
 ```
 
 ## How the CSV Sink Works

docs/connectors/sinks/influxdb3-sink.md

@@ -33,6 +33,9 @@ sdf = app.dataframe(topic)
 # Do some processing here ...
 # Sink data to InfluxDB
 sdf.sink(influx_sink)
+
+if __name__ == '__main__':
+    app.run()
 ```
 
 ## How the InfluxDB Sink Works

docs/connectors/sources/README.md

@@ -53,15 +53,15 @@ from quixstreams.sources import CSVSource
 from quixstreams.models.topics import TopicConfig
 
 def main():
-  app = Application()
-  source = CSVSource(path="input.csv")
-  topic = app.topic("my_csv_source", config=TopicConfig(num_partitions=4, replication_factor=1))
-
-  sdf = app.dataframe(topic=topic, source=source)
-  sdf.print(metadata=True)
-
-  app.run()
+    app = Application()
+    source = CSVSource(path="input.csv")
+    topic = app.topic("my_csv_source", config=TopicConfig(num_partitions=4, replication_factor=1))
+    
+    sdf = app.dataframe(topic=topic, source=source)
+    sdf.print(metadata=True)
+    
+    app.run()
 
 if __name__ == "__main__":
-  main()
+    main()
 ```

docs/connectors/sources/custom-sources.md

@@ -73,16 +73,16 @@ class MySource(Source):
             time.sleep(1)
 
 def main():
-  app = Application(broker_address="localhost:19092")
-  source = MySource(name="mysource")
+    app = Application(broker_address="localhost:19092")
+    source = MySource(name="mysource")
 
-  sdf = app.dataframe(source=source)
-  sdf.print(metadata=True)
+    sdf = app.dataframe(source=source)
+    sdf.print(metadata=True)
 
-  app.run()
+    app.run()
 
 if __name__ == "__main__":
-  main()
+    main()
 ```
 
 ```

docs/connectors/sources/kafka-source.md

@@ -13,21 +13,21 @@ from quixstreams import Application
 from quixstreams.sources import KafkaReplicatorSource
 
 def main():
-  app = Application()
-  source = KafkaReplicatorSource(
+    app = Application()
+    source = KafkaReplicatorSource(
     name="my-source",
     app_config=app.config,
     topic="source-topic",
     broker_address="source-broker-address"
-  )
-
-  sdf = app.dataframe(source=source)
-  sdf.print(metadata=True)
-
-  app.run()
+    )
+    
+    sdf = app.dataframe(source=source)
+    sdf.print(metadata=True)
+    
+    app.run()
 
 if __name__ == "__main__":
-  main()
+    main()
 ```
 
 ## Topic

docs/connectors/sources/quix-source.md

@@ -11,24 +11,24 @@ from quixstreams import Application
 from quixstreams.sources import QuixEnvironmentSource
 
 def main():
-  app = Application()
-  source = QuixEnvironmentSource(
+    app = Application()
+    source = QuixEnvironmentSource(
     name="my-source",
     app_config=app.config,
     topic="source-topic",
     quix_sdk_token="quix-sdk-token",
     quix_workspace_id="quix-workspace-id",
-  )
-
-  sdf = app.dataframe(source=source)
-  sdf.print(metadata=True)
-
-  app.run()
+    )
+    
+    sdf = app.dataframe(source=source)
+    sdf.print(metadata=True)
+    
+    app.run()
 
 if __name__ == "__main__":
-  main()
+    main()
 ```
 
-## Token
+## SDK Token
 
-The Quix Environment Source requires the sdk token of the source environment. [Click here](../../../develop/authentication/streaming-token.md) for more information on SDK tokens.
+The Quix Environment Source requires the SDK token of the source environment. [Click here](../../../develop/authentication/streaming-token.md) for more information on SDK tokens.

docs/processing.md

@@ -40,16 +40,23 @@ In general, when operations are added, they should follow a "reassignment" patte
 to ensure they are applied correctly. For example:
 
 ```python
-# NOTE: this is an incomplete stub just to show usage
 from quixstreams import Application
 
-sdf = Application().dataframe()
+# Initialize the Appication
+app = Application(...)
+
+# Create a StreamingDataFrame
+sdf = app.dataframe()
 
 # re-assign sdf with an added operation
 sdf = sdf.apply(lambda x: x + 1)
 
 # add two more operations at once ("chaining" operations)
 sdf = sdf.apply(lambda x: x + 2).apply(lambda x: x + 3)
+
+# Run the application
+if __name__ == '__main__':
+    app.run()
 ```
 
 This pattern is safe to use for almost every operation with `StreamingDataFrames`; any