Add detailed godoc documentation to CLIEntry function

Expand the documentation comment for CLIEntry to provide more context
about what the function does, including its use of the fx dependency
injection framework, signal handling, and blocking behavior.

internal/database/models.go

@@ -1,3 +1,4 @@
+// Package database provides SQLite storage for BGP routing data.
 package database
 
 import (
@@ -6,7 +7,8 @@ import (
 	"github.com/google/uuid"
 )
 
-// ASN represents an Autonomous System Number
+// ASN represents an Autonomous System Number with its metadata including
+// handle, description, and first/last seen timestamps.
 type ASN struct {
 	ASN         int       `json:"asn"`
 	Handle      string    `json:"handle"`