refactor: consolidate CLI command definitions to lib.rs

- Move all CLI command enums (ChannelCommands, SkillCommands, CronCommands, IntegrationCommands, MigrateCommands, ServiceCommands) to lib.rs
- Add clap derives for use in main.rs CLI parsing
- Update all modules to use crate:: prefix instead of super:: for command types
- Add mod util; to main.rs for binary compilation
- Export Config type from lib.rs for main.rs

This refactoring eliminates code duplication between library modules and binary, centralizing all CLI command definitions in one place.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/cron/mod.rs

@@ -19,9 +19,9 @@ pub struct CronJob {
 }
 
 #[allow(clippy::needless_pass_by_value)]
-pub fn handle_command(command: super::CronCommands, config: &Config) -> Result<()> {
+pub fn handle_command(command: crate::CronCommands, config: &Config) -> Result<()> {
     match command {
-        super::CronCommands::List => {
+        crate::CronCommands::List => {
             let jobs = list_jobs(config)?;
             if jobs.is_empty() {
                 println!("No scheduled tasks yet.");
@@ -48,7 +48,7 @@ pub fn handle_command(command: super::CronCommands, config: &Config) -> Result<(
             }
             Ok(())
         }
-        super::CronCommands::Add {
+        crate::CronCommands::Add {
             expression,
             command,
         } => {
@@ -59,7 +59,7 @@ pub fn handle_command(command: super::CronCommands, config: &Config) -> Result<(
             println!("  Cmd : {}", job.command);
             Ok(())
         }
-        super::CronCommands::Remove { id } => remove_job(config, &id),
+        crate::CronCommands::Remove { id } => remove_job(config, &id),
     }
 }