feat(cli): add documentation to main entry point

feat(composer): improve main module documentation

feat(sequencer): enhance main entry point documentation

These changes add helpful documentation comments to improve code clarity and understanding for developers working on these components.

Author: warhod

crates/astria-cli/src/main.rs

@@ -1,5 +1,7 @@
 use color_eyre::eyre;
 
+/// Main entry point for the Astria CLI application.
+/// Initializes logging and runs the CLI interface.
 #[tokio::main]
 async fn main() -> eyre::Result<()> {
     tracing_subscriber::fmt()

crates/astria-composer/src/main.rs

@@ -1,3 +1,6 @@
+//! Main entry point for the Astria Composer service.
+//! Handles transaction composition and batching for the Astria network.
+
 use std::process::ExitCode;
 
 use astria_composer::{

crates/astria-sequencer/src/main.rs

@@ -1,3 +1,6 @@
+//! Main entry point for the Astria Sequencer node.
+//! Handles block production and transaction sequencing for the Astria network.
+
 use std::process::ExitCode;
 
 use astria_eyre::eyre::WrapErr as _;