feat: support azure entraid for managed redis - #776

@@ -105,11 +105,38 @@
 ```go
 cache.InitRedisClient(
     addr,      // "localhost:6379"
-    username,  // optional
-    password,  
+    cache.RedisCredentials{
+        Username: username,  // optional
+        Password: password,
+    },
     useSsl,    // bool
     db,        // database number
+    tlsConf,   // *tls.Config, can be nil
 )
+```
+
+### Azure Entra ID Authentication
+
+The daemon supports Azure Managed Identity (Entra ID) for Redis authentication.
+This is configured using the `REDIS_USE_AZURE_MANAGED_IDENTITY` environment variable.
+When enabled, static `REDIS_PASSWORD`/`REDIS_USERNAME` are ignored and a streaming
+token provider is used instead. Azure Managed Redis requires `REDIS_DB=0` (the system
+validates this at startup).
+
+```go
+creds := cache.RedisCredentials{
+    Username: username,
+    Password: password,
+}
+if useAzureManagedIdentity {
+    provider, err := cache.NewAzureEntraIDCredentialsProvider()
+    if err != nil {
+        // handle error
+    }
+    creds.CredentialProvider = provider
+}
+
+cache.InitRedisClient(addr, creds, useSsl, db, tlsConf)
 ```
 
 Redis naming behavior: