feat: enhance evobgp with new command-line tools for bundle management, including pull, verify, and apply functionalities. Update go.mod to include necessary dependencies and complete todos in architecture plan for improved observability and deployment practices.

internal/birdfmt/fragment.go

@@ -0,0 +1,47 @@
+package birdfmt
+
+import (
+	"fmt"
+	"strings"
+)
+
+// ManagedBanner returns a comment block marking EvoBGP-generated files (optional first line in bird.d/*.conf).
+func ManagedBanner(revisionHint string) string {
+	rev := strings.TrimSpace(revisionHint)
+	var b strings.Builder
+	b.WriteString("# EvoBGP generated — do not edit by hand.\n")
+	if rev != "" {
+		b.WriteString("# Revision: ")
+		b.WriteString(rev)
+		b.WriteByte('\n')
+	}
+	return b.String()
+}
+
+// JoinFragments concatenates non-empty text blocks with a blank line between them.
+func JoinFragments(parts ...string) string {
+	var out []string
+	for _, p := range parts {
+		p = strings.TrimSpace(p)
+		if p == "" {
+			continue
+		}
+		out = append(out, p)
+	}
+	if len(out) == 0 {
+		return ""
+	}
+	return strings.Join(out, "\n\n") + "\n"
+}
+
+// ValidateIncludePath rejects paths that could break out of the config directory.
+func ValidateIncludePath(p string) error {
+	p = strings.TrimSpace(p)
+	if p == "" {
+		return fmt.Errorf("birdfmt: include path is empty")
+	}
+	if strings.Contains(p, "..") {
+		return fmt.Errorf("birdfmt: include path must not contain '..': %q", p)
+	}
+	return nil
+}