feat(config): integrate etcd for service discovery and config management

- Add etcd-client dependency for distributed configuration storage
- Implement EtcdConfig with priority: etcd > environment variables > defaults
- Add ServiceRegistry for service registration with lease keep-alive
- Integrate etcd-based service discovery for appks gRPC connections
- Add service watcher for real-time service instance updates
- Migrate Redis configuration from single URL to cluster node list
- Update Dockerfile with default IMKS_HOST and IMKS_PORT environment variables
- Add etcd bootstrap configuration through environment variables
- Implement Redis cluster URL building with optional authentication

Cargo.lock

@@ -262,6 +262,12 @@ dependencies = [
  "rustversion",
 ]
 
+[[package]]
+name = "arcstr"
+version = "1.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "03918c3dbd7701a85c6b9887732e2921175f26c350b4563841d0958c21d57e6d"
+
 [[package]]
 name = "asn1-rs"
 version = "0.7.2"
@@ -301,6 +307,17 @@ dependencies = [
  "syn",
 ]
 
+[[package]]
+name = "async-lock"
+version = "3.4.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "290f7f2596bd5b78a9fec8088ccd89180d7f9f55b94b0576823bbbdc72ee8311"
+dependencies = [
+ "event-listener",
+ "event-listener-strategy",
+ "pin-project-lite",
+]
+
 [[package]]
 name = "async-nats"
 version = "0.38.0"
@@ -412,6 +429,15 @@ dependencies = [
  "tower-service",
 ]
 
+[[package]]
+name = "backon"
+version = "1.6.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "cffb0e931875b666fc4fcb20fee52e9bbd1ef836fd9e9e04ec21555f9f85f7ef"
+dependencies = [
+ "fastrand",
+]
+
 [[package]]
 name = "base64"
 version = "0.22.1"
@@ -502,16 +528,6 @@ dependencies = [
  "serde",
 ]
 
-[[package]]
-name = "bytes-utils"
-version = "0.1.4"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "7dafe3a8757b027e2be6e4e5601ed563c55989fcf1546e933c66c8eb3a058d35"
-dependencies = [
- "bytes",
- "either",
-]
-
 [[package]]
 name = "bytestring"
 version = "1.5.1"
@@ -576,6 +592,20 @@ version = "0.5.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "0c9ea0ac24bc397ab3c98583a3c9ba74fa56b09a4449bbe172b9b1ddb016027a"
 
+[[package]]
+name = "combine"
+version = "4.6.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ba5a308b75df32fe02788e748662718f03fde005016435c444eea572398219fd"
+dependencies = [
+ "bytes",
+ "futures-core",
+ "memchr",
+ "pin-project-lite",
+ "tokio",
+ "tokio-util",
+]
+
 [[package]]
 name = "concurrent-queue"
 version = "2.5.0"
@@ -617,12 +647,6 @@ dependencies = [
  "version_check",
 ]
 
-[[package]]
-name = "cookie-factory"
-version = "0.3.2"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "396de984970346b0d9e93d1415082923c679e5ae5c3ee3dcbd104f5610af126b"
-
 [[package]]
 name = "core-foundation"
 version = "0.9.4"
@@ -978,6 +1002,16 @@ dependencies = [
  "pin-project-lite",
 ]
 
+[[package]]
+name = "event-listener-strategy"
+version = "0.5.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8be9f3dfaaffdae2972880079a491a1a8bb7cbed0b8dd7a347f668b4150a3b93"
+dependencies = [
+ "event-listener",
+ "pin-project-lite",
+]
+
 [[package]]
 name = "fastrand"
 version = "2.4.1"
@@ -1012,15 +1046,6 @@ dependencies = [
  "miniz_oxide",
 ]
 
-[[package]]
-name = "float-cmp"
-version = "0.10.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b09cf3155332e944990140d967ff5eceb70df778b34f77d8075db46e4704e6d8"
-dependencies = [
- "num-traits",
-]
-
 [[package]]
 name = "flume"
 version = "0.12.0"
@@ -1059,43 +1084,6 @@ dependencies = [
  "percent-encoding",
 ]
 
-[[package]]
-name = "fred"
-version = "10.1.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "3a7b2fd0f08b23315c13b6156f971aeedb6f75fb16a29ac1872d2eabccc1490e"
-dependencies = [
- "arc-swap",
- "async-trait",
- "bytes",
- "bytes-utils",
- "float-cmp",
- "fred-macros",
- "futures",
- "log",
- "parking_lot",
- "rand 0.8.6",
- "redis-protocol",
- "semver",
- "socket2 0.5.10",
- "tokio",
- "tokio-stream",
- "tokio-util",
- "url",
- "urlencoding",
-]
-
-[[package]]
-name = "fred-macros"
-version = "0.1.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "1458c6e22d36d61507034d5afecc64f105c1d39712b7ac6ec3b352c423f715cc"
-dependencies = [
- "proc-macro2",
- "quote",
- "syn",
-]
-
 [[package]]
 name = "futures"
 version = "0.3.32"
@@ -1104,7 +1092,6 @@ checksum = "8b147ee9d1f6d097cef9ce628cd2ee62288d963e16fb287bd9286455b241382d"
 dependencies = [
  "futures-channel",
  "futures-core",
- "futures-executor",
  "futures-io",
  "futures-sink",
  "futures-task",
@@ -1630,8 +1617,8 @@ dependencies = [
  "base64",
  "chrono",
  "dashmap",
+ "dotenvy",
  "etcd-client",
- "fred",
  "futures-util",
  "jsonwebtoken",
  "opentelemetry",
@@ -1643,6 +1630,7 @@ dependencies = [
  "prost",
  "prost-types",
  "rand 0.9.4",
+ "redis",
  "serde",
  "serde_json",
  "sqlx",
@@ -2534,17 +2522,34 @@ dependencies = [
 ]
 
 [[package]]
-name = "redis-protocol"
-version = "6.0.0"
+name = "redis"
+version = "1.2.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "9cdba59219406899220fc4cdfd17a95191ba9c9afb719b5fa5a083d63109a9f1"
+checksum = "a12e6b5f4d8ef33944e833e2b1859ad478deab6e431d7337b30ee2efe21f7543"
 dependencies = [
+ "arc-swap",
+ "arcstr",
+ "async-lock",
+ "backon",
  "bytes",
- "bytes-utils",
- "cookie-factory",
+ "cfg-if",
+ "combine",
  "crc16",
+ "futures-channel",
+ "futures-util",
+ "itoa",
  "log",
- "nom",
+ "num-bigint",
+ "percent-encoding",
+ "pin-project-lite",
+ "rand 0.9.4",
+ "ryu",
+ "sha1_smol",
+ "socket2 0.6.4",
+ "tokio",
+ "tokio-util",
+ "url",
+ "xxhash-rust",
 ]
 
 [[package]]
@@ -2918,6 +2923,12 @@ dependencies = [
  "digest 0.11.3",
 ]
 
+[[package]]
+name = "sha1_smol"
+version = "1.0.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "bbfa15b3dddfee50a0fff136974b3e1bde555604ba463834a7eb7deb6417705d"
+
 [[package]]
 name = "sha2"
 version = "0.10.9"
@@ -3813,12 +3824,6 @@ dependencies = [
  "serde",
 ]
 
-[[package]]
-name = "urlencoding"
-version = "2.1.3"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "daf8dba3b7eb870caf1ddeed7bc9d2a049f3cfdfae7cb521b087cc33ae4c49da"
-
 [[package]]
 name = "utf8_iter"
 version = "1.0.4"
@@ -4317,6 +4322,12 @@ dependencies = [
  "time",
 ]
 
+[[package]]
+name = "xxhash-rust"
+version = "0.8.15"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "fdd20c5420375476fbd4394763288da7eb0cc0b8c11deed431a91562af7335d3"
+
 [[package]]
 name = "yasna"
 version = "0.6.0"