Show and edit option values laid out as in named.conf

Values with blocks (logging, controls, ...) are shown over several lines
with indentation, and edited that way: the editor grows with its content,
Tab indents, Enter keeps the indentation. With a draft open, option tables
show the draft's values.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

internal/api/types.go

@@ -77,6 +77,10 @@ type Option struct {
 	Where       string `json:"where"` // e.g. "view internal"
 	Description string `json:"description,omitempty"`
 	Status      string `json:"status,omitempty"`
+	// Formatted is the value laid out over several lines, as in
+	// named.conf, when it has a block (for display and editing; Value is
+	// the same on one line).
+	Formatted string `json:"formatted,omitempty"`
 }
 
 // User is a user with formatted grants.