Have the coins pallet emit events via serai_core_pallet

`serai_core_pallet` solely defines an accumulator for the events. We use the
traditional `frame_system::Events` to store them for now and enable retrieval.

Cargo.lock

@@ -1836,9 +1836,9 @@ dependencies = [
 
 [[package]]
 name = "clap"
-version = "4.5.47"
+version = "4.5.48"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "7eac00902d9d136acd712710d71823fb8ac8004ca445a89e73a41d45aa712931"
+checksum = "e2134bb3ea021b78629caa971416385309e0131b351b25e01dc16fb54e1b5fae"
 dependencies = [
  "clap_builder",
  "clap_derive",
@@ -1846,9 +1846,9 @@ dependencies = [
 
 [[package]]
 name = "clap_builder"
-version = "4.5.47"
+version = "4.5.48"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "2ad9bbf750e73b5884fb8a211a9424a1906c1e156724260fdae972f31d70e1d6"
+checksum = "c2ba64afa3c0a6df7fa517765e31314e983f51dda798ffba27b988194fb65dc9"
 dependencies = [
  "anstream",
  "anstyle",
@@ -8899,14 +8899,14 @@ dependencies = [
 name = "serai-coins-pallet"
 version = "0.1.0"
 dependencies = [
+ "borsh",
  "frame-support",
  "frame-system",
  "parity-scale-codec",
- "serai-primitives",
+ "serai-abi",
+ "serai-core-pallet",
  "sp-core",
  "sp-io",
- "sp-runtime",
- "sp-std",
 ]
 
 [[package]]
@@ -9029,7 +9029,6 @@ dependencies = [
  "parity-scale-codec",
  "serai-abi",
  "sp-core",
- "sp-io",
 ]
 
 [[package]]
@@ -9697,7 +9696,6 @@ dependencies = [
 name = "serai-runtime"
 version = "0.1.0"
 dependencies = [
- "borsh",
  "frame-executive",
  "frame-support",
  "frame-system",
@@ -9724,7 +9722,6 @@ dependencies = [
  "serai-abi",
  "serai-validator-sets-pallet",
  "sp-core",
- "sp-io",
 ]
 
 [[package]]