chore: add missing crate descriptions for crates.io publishing (#129)

Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: prestwich

crates/blobber/Cargo.toml

@@ -1,5 +1,6 @@
 [package]
 name = "signet-blobber"
+description = "Blob fetching, caching, and block extraction for the Signet node"
 version.workspace = true
 edition.workspace = true
 rust-version.workspace = true

crates/genesis/Cargo.toml

@@ -1,5 +1,6 @@
 [package]
 name = "signet-genesis"
+description = "Genesis configuration and chain specification loading for Signet networks"
 version.workspace = true
 edition.workspace = true
 rust-version.workspace = true

crates/node-config/Cargo.toml

@@ -1,5 +1,6 @@
 [package]
 name = "signet-node-config"
+description = "Environment-driven configuration for the Signet node"
 version.workspace = true
 edition.workspace = true
 rust-version.workspace = true

crates/node-tests/Cargo.toml

@@ -1,5 +1,6 @@
 [package]
 name = "signet-node-tests"
+description = "Integration test scaffolding and tests for the Signet node"
 version.workspace = true
 edition.workspace = true
 rust-version.workspace = true

crates/node/Cargo.toml

@@ -1,5 +1,6 @@
 [package]
 name = "signet-node"
+description = "Core Signet rollup node: block processing, state management, and lifecycle orchestration"
 version.workspace = true
 edition.workspace = true
 rust-version.workspace = true