feat: Add main entry point and all CLI commands

- cmd/claudia-docs/main.go - entry point
- cobra/commands.go - CLI commands
- internal/api/ - HTTP client and API calls
- internal/auth/ - authentication
- internal/config/ - configuration
- internal/output/ - output formatting
- pkg/types/ - shared types

cmd/claudia-docs/main.go

@@ -0,0 +1,13 @@
+package main
+
+import (
+	"os"
+
+	"github.com/claudia/docs-cli/cobra"
+)
+
+func main() {
+	if err := cobra.Execute(); err != nil {
+		os.Exit(1)
+	}
+}