Add Airflow and Kafka broker configs to git

- config/airflow/airflow.cfg (fernet/API keys redacted) + live DAG sync
- config/kafka/kraft-server.properties (live KRaft broker on kafka01)
- Extend collect-fleet-config.sh for airflow/kafka collection
- Add docs/recommendations.md with prioritized next steps

config/kafka/kraft-server.properties

@@ -0,0 +1,35 @@
+# Required KRaft roles
+process.roles=broker,controller
+node.id=1
+controller.quorum.voters=1@localhost:9093
+
+# Listeners
+listeners=PLAINTEXT://0.0.0.0:9092,CONTROLLER://0.0.0.0:9093
+controller.listener.names=CONTROLLER
+inter.broker.listener.name=PLAINTEXT
+advertised.listeners=PLAINTEXT://10.0.21.36:9092
+listener.security.protocol.map=CONTROLLER:PLAINTEXT,PLAINTEXT:PLAINTEXT
+
+# Storage - use a clean directory
+log.dirs=/home/kafka/data
+
+# Topic defaults
+num.partitions=3
+default.replication.factor=1
+
+# Retention (7 days)
+log.retention.hours=168
+log.retention.check.interval.ms=300000
+log.segment.bytes=1073741824
+
+# Performance (8 vCPUs)
+num.network.threads=8
+num.io.threads=8
+socket.send.buffer.bytes=102400
+socket.receive.buffer.bytes=102400
+socket.request.max.bytes=104857600
+
+# Transaction state (single node)
+offsets.topic.replication.factor=1
+transaction.state.log.replication.factor=1
+transaction.state.log.min.isr=1