Add redis: Boot 4.1 + Spring Data Redis 4.1, the JDK-serialisation default vs Jackson 3 serializers, @RedisHash TTL and keyspace events, @RedisListener, and Redis as the Spring cache

Co-Authored-By: Claude Sonnet 5 <[email protected]>
Claude-Session: https://claude.ai/code/session_01B38FGKKam5SCGgwgduVAh3

redis/docs/output/01-default-template.txt

@@ -0,0 +1,20 @@
+# The RedisTemplate Boot gives you: JDK serialisation for keys and values
+
+
+--- Which serializers is it using? ---
+key serializer:   JdkSerializationRedisSerializer
+value serializer: JdkSerializationRedisSerializer
+
+--- Write a String under the key user:1 ---
+redisTemplate.opsForValue().set("user:1", "Ankur")
+
+--- What redis-cli sees ---
+$ redis-cli -p 6390 --no-raw KEYS '*'
+1) "\xac\xed\x00\x05t\x00\x06user:1"
+$ redis-cli -p 6390 --no-raw GET user:1
+(nil)
+$ redis-cli -p 6390 --no-raw EVAL 'return redis.call("GET", redis.call("KEYS", "*")[1])' 0
+"\xac\xed\x00\x05t\x00\x05Ankur"
+
+--- What Java sees ---
+redisTemplate.opsForValue().get("user:1") = Ankur