Add support for never_be_nested metadata.

lib/pages/creature-page.tsx

@@ -39,7 +39,10 @@ const ATTACHMENT_SYMBOLS = ROOT_SYMBOLS;
 
 /** Symbols that can be nested within any part of a creature. */
 const NESTED_SYMBOLS = SvgVocabulary.filter(
-  (data) => data.meta?.always_nest !== true
+  // Since we don't currently support recursive nesting, ignore anything that
+  // wants nested children.
+  (data) =>
+    data.meta?.always_nest !== true && data.meta?.never_be_nested !== true
 );
 
 /**

lib/svg-symbol-metadata.ts

@@ -10,11 +10,18 @@ type SvgSymbolMetadataBooleans = {
    * be nested inside another symbol's nesting area.
    */
   always_be_nested?: boolean;
+
+  /**
+   * If true, this indicates that the symbol should never
+   * be nested inside another symbol's nesting area.
+   */
+  never_be_nested?: boolean;
 };
 
 const METADATA_BOOLEANS: Set<keyof SvgSymbolMetadataBooleans> = new Set([
   "always_nest",
   "always_be_nested",
+  "never_be_nested",
 ]);
 
 function isSvgSymbolMetadataBoolean(

svg/_template.toml

@@ -15,3 +15,7 @@ always_nest = false
 # If true, this indicates that the symbol should always
 # be nested inside another symbol's nesting area.
 always_be_nested = false
+
+# If true, this indicates that the symbol should never
+# be nested inside another symbol's nesting area.
+never_be_nested = false