[feature] implementation of the settlement pipeline

Cargo.toml

@@ -1,6 +1,6 @@
 [workspace]
 members = [
-    "crates/matching-engine",
+    "crates/matching_engine",
     "crates/settlement",
     "crates/gateway",
     "crates/indexer",
@@ -16,8 +16,22 @@ license = "MIT"
 
 
 [workspace.dependencies]
+# Local workspace members
+matching_engine = { path = "crates/matching_engine" }
+common = { path = "crates/common" }
+
+# Shared external dependencies
 rust_decimal = "1.40.0"
 uuid = { version = "1.10.0", features = ["v4", "serde"] }
 serde = { version = "1.0.210", features = ["derive"] }
 serde_json = "1.0.149"
 thiserror = "2.0.18"
+tokio = { version = "1.49.0", features = ["full"] }
+tokio-util = { version = "0.7.18", features = ["time"] }
+anyhow = "1.0.101"
+tracing = "0.1.44"
+tracing-subscriber = "0.3.22"
+metrics = "0.24.3"
+metrics-exporter-prometheus = "0.18.1"
+revm = { version = "34.0.0", features = ["std", "serde"] }
+futures = "0.3.31"

README.md

@@ -1,3 +1,4 @@
 # Meridian Protocol.
 
-Biggest gas saving in the contract: 256 nonce per storage slot. A trader submitting 256 fills in one block touches only 1 cold SLOAD + 1 SSTORE instead of 256.
+Biggest gas saving in the contract: 256 nonce per storage slot. 
+A trader submitting 256 fills in one block touches only 1 cold SLOAD + 1 SSTORE instead of 256.

crates/matching-engine/Cargo.toml → crates/matching_engine/Cargo.toml

@@ -1,5 +1,5 @@
 [package]
-name = "matching-engine"
+name = "matching_engine"
 version.workspace = true
 edition.workspace = true
 

crates/settlement/Cargo.toml

@@ -4,3 +4,30 @@ version.workspace = true
 edition.workspace = true
 
 [dependencies]
+matching_engine = { workspace = true }
+common = {workspace = true}
+tokio = {workspace = true}
+serde = {workspace = true}
+thiserror = {workspace = true}
+anyhow = {workspace = true}
+uuid = {workspace = true}
+rust_decimal = {workspace = true}
+tracing = {workspace = true}
+
+alloy = { version = "1.6.3", features = [
+    "full",
+    "node-bindings",
+    "rpc-types",
+    "provider-http",
+    "signers",
+    "signer-local",
+    "contract",
+    "sol-types"
+] }
+
+revm = {workspace = true}
+tokio-util = {workspace = true}
+futures = {workspace = true}
+tracing-subscriber = {workspace = true}
+metrics = {workspace = true}
+metrics-exporter-prometheus = {workspace = true}

crates/settlement/src/README.MD

@@ -0,0 +1,5 @@
+For batch flush trigger, when ANY of these conditions are met:
+1. fills >= MAX_BATCH_SIZE (eg 50)                               - size cap
+2. elapsed >= MAX_BATCH_AGE_MS (eg 500ms)                        - latency cap
+3. gas_price <= GAS_PRICE_THRESHOLD                              - opportunistic flush ( dynamic gas price trigger)
+4. fills >= MIN_BATCH_SIZE && gas_price is below rolling average - smart: only flush small batches when gas is cheap.