feat(cli): add colorful styled help output with categorized options (#275)

- Add clap styling with cyan headers, green commands, yellow placeholders
- Add ASCII art banner to help output
- Categorize options into Model Configuration, Security, Workspace, Features, Debugging
- Add colored environment variables and examples in after-help section
- Organize subcommands by display_order for logical grouping
- Add color-print dependency for styled after-help content

Co-authored-by: Droid Agent <droid@factory.ai>

Author: echobt

Cargo.lock

@@ -39,6 +39,9 @@ cortex-share = { path = "../cortex-share" }
 clap = { workspace = true }
 clap_complete = { workspace = true }
 clap_mangen = { workspace = true }
+
+# For colored help output
+color-print = "0.3"
 tokio = { workspace = true, features = ["full"] }
 anyhow = { workspace = true }
 tracing = { workspace = true }