feat(sync): Phase 6 - observability and production readiness

- Add SyncMetrics with full Prometheus integration
- Track sync gaps via catchup events
- Update Grafana dashboard with sync panels
- Document all sync configuration options
- Update design doc with implementation notes

1 files changed, 157 insertions, 3 deletions

diff --git a/Cargo.lock b/Cargo.lock
index a035f75..4f7835b 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -774,7 +774,7 @@ dependencies = [
  "futures",
  "nostr-sdk 0.43.0",
  "regex",
- "reqwest",
+ "reqwest 0.11.27",
  "serde",
  "serde_json",
  "tempfile",
@@ -1022,6 +1022,22 @@ dependencies = [
 ]
 
 [[package]]
+name = "hyper-rustls"
+version = "0.27.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e3c93eb611681b207e1fe55d5a71ecf91572ec8a6705cdb6857f7d8d5242cf58"
+dependencies = [
+ "http 1.3.1",
+ "hyper 1.8.1",
+ "hyper-util",
+ "rustls",
+ "rustls-pki-types",
+ "tokio",
+ "tokio-rustls",
+ "tower-service",
+]
+
+[[package]]
 name = "hyper-tls"
 version = "0.5.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
@@ -1035,18 +1051,45 @@ dependencies = [
 ]
 
 [[package]]
+name = "hyper-tls"
+version = "0.6.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "70206fc6890eaca9fde8a0bf71caa2ddfc9fe045ac9e5c70df101a7dbde866e0"
+dependencies = [
+ "bytes",
+ "http-body-util",
+ "hyper 1.8.1",
+ "hyper-util",
+ "native-tls",
+ "tokio",
+ "tokio-native-tls",
+ "tower-service",
+]
+
+[[package]]
 name = "hyper-util"
 version = "0.1.18"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "52e9a2a24dc5c6821e71a7030e1e14b7b632acac55c40e9d2e082c621261bb56"
 dependencies = [
+ "base64 0.22.1",
  "bytes",
+ "futures-channel",
  "futures-core",
+ "futures-util",
  "http 1.3.1",
  "http-body 1.0.1",
  "hyper 1.8.1",
+ "ipnet",
+ "libc",
+ "percent-encoding",
  "pin-project-lite",
+ "socket2 0.6.1",
+ "system-configuration",
  "tokio",
+ "tower-service",
+ "tracing",
+ "windows-registry",
 ]
 
 [[package]]
@@ -1214,6 +1257,16 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "469fb0b9cefa57e3ef31275ee7cacb78f2fdca44e4765491884a2b119d4eb130"
 
 [[package]]
+name = "iri-string"
+version = "0.7.9"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4f867b9d1d896b67beb18518eda36fdb77a32ea590de864f1325b294a6d14397"
+dependencies = [
+ "memchr",
+ "serde",
+]
+
+[[package]]
 name = "is_terminal_polyfill"
 version = "1.70.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
@@ -1385,6 +1438,8 @@ dependencies = [
  "nostr-relay-builder",
  "nostr-sdk 0.44.1",
  "prometheus",
+ "rand 0.8.5",
+ "reqwest 0.12.24",
  "serde",
  "serde_json",
  "tempfile",
@@ -1956,7 +2011,7 @@ dependencies = [
  "http 0.2.12",
  "http-body 0.4.6",
  "hyper 0.14.32",
- "hyper-tls",
+ "hyper-tls 0.5.0",
  "ipnet",
  "js-sys",
  "log",
@@ -1969,7 +2024,7 @@ dependencies = [
  "serde",
  "serde_json",
  "serde_urlencoded",
- "sync_wrapper",
+ "sync_wrapper 0.1.2",
  "system-configuration",
  "tokio",
  "tokio-native-tls",
@@ -1982,6 +2037,46 @@ dependencies = [
 ]
 
 [[package]]
+name = "reqwest"
+version = "0.12.24"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9d0946410b9f7b082a427e4ef5c8ff541a88b357bc6c637c40db3a68ac70a36f"
+dependencies = [
+ "base64 0.22.1",
+ "bytes",
+ "encoding_rs",
+ "futures-core",
+ "h2 0.4.12",
+ "http 1.3.1",
+ "http-body 1.0.1",
+ "http-body-util",
+ "hyper 1.8.1",
+ "hyper-rustls",
+ "hyper-tls 0.6.0",
+ "hyper-util",
+ "js-sys",
+ "log",
+ "mime",
+ "native-tls",
+ "percent-encoding",
+ "pin-project-lite",
+ "rustls-pki-types",
+ "serde",
+ "serde_json",
+ "serde_urlencoded",
+ "sync_wrapper 1.0.2",
+ "tokio",
+ "tokio-native-tls",
+ "tower",
+ "tower-http",
+ "tower-service",
+ "url",
+ "wasm-bindgen",
+ "wasm-bindgen-futures",
+ "web-sys",
+]
+
+[[package]]
 name = "ring"
 version = "0.17.14"
 source = "registry+https://github.com/rust-lang/crates.io-index"
@@ -2347,6 +2442,15 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "2047c6ded9c721764247e62cd3b03c09ffc529b2ba5b10ec482ae507a4a70160"
 
 [[package]]
+name = "sync_wrapper"
+version = "1.0.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0bf256ce5efdfa370213c1dabab5935a12e49f2c58d15e9eac2870d3b4f27263"
+dependencies = [
+ "futures-core",
+]
+
+[[package]]
 name = "synchronoise"
 version = "1.0.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
@@ -2588,6 +2692,45 @@ dependencies = [
 ]
 
 [[package]]
+name = "tower"
+version = "0.5.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d039ad9159c98b70ecfd540b2573b97f7f52c3e8d9f8ad57a24b916a536975f9"
+dependencies = [
+ "futures-core",
+ "futures-util",
+ "pin-project-lite",
+ "sync_wrapper 1.0.2",
+ "tokio",
+ "tower-layer",
+ "tower-service",
+]
+
+[[package]]
+name = "tower-http"
+version = "0.6.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9cf146f99d442e8e68e585f5d798ccd3cad9a7835b917e09728880a862706456"
+dependencies = [
+ "bitflags 2.10.0",
+ "bytes",
+ "futures-util",
+ "http 1.3.1",
+ "http-body 1.0.1",
+ "iri-string",
+ "pin-project-lite",
+ "tower",
+ "tower-layer",
+ "tower-service",
+]
+
+[[package]]
+name = "tower-layer"
+version = "0.3.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "121c2a6cda46980bb0fcd1647ffaf6cd3fc79a013de288782836f6df9c48780e"
+
+[[package]]
 name = "tower-service"
 version = "0.3.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
@@ -2949,6 +3092,17 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "f0805222e57f7521d6a62e36fa9163bc891acd422f971defe97d64e70d0a4fe5"
 
 [[package]]
+name = "windows-registry"
+version = "0.6.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "02752bf7fbdcce7f2a27a742f798510f3e5ad88dbe84871e5168e2120c3d5720"
+dependencies = [
+ "windows-link",
+ "windows-result",
+ "windows-strings",
+]
+
+[[package]]
 name = "windows-result"
 version = "0.4.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"