fix(acl): a missing allow_ip_literals means allowed (#261)

The Server ACL editor treated an absent allow_ip_literals as false, so the
first save in a room with no ACL (or one omitting the field) silently banned
IP-literal servers. The spec default is true. normalizeServerAcl() fills the
spec defaults once and feeds the initial state, the dirty check and the save.
It also stops showing an existing ACL with no allow list as allow-all: per
spec that allows no servers, and the /acl command already keeps it as-is.

The checkbox is driven by onClick (folds has no onChange), now readOnly so
React stops warning about a checked input without onChange.

Fixes #261

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_017PCb59uY3UKqDqt7B6hzd5

src/app/utils/serverAcl.ts

@@ -50,3 +50,29 @@ export function matchesAnyGlob(domain: string, globs: string[]): boolean {
     }
   });
 }
+
+/**
+ * `m.room.server_acl` content with the spec's defaults filled in (#261).
+ * `allow_ip_literals` defaults to **true** when absent; `allow` and `deny`
+ * default to empty lists, but with no ACL event at all every server is allowed,
+ * so the editor starts from `allow: ['*']` in that case.
+ * https://spec.matrix.org/v1.12/client-server-api/#mroomserver_acl
+ */
+export type ServerAclContent = {
+  allow: string[];
+  deny: string[];
+  allow_ip_literals: boolean;
+};
+
+const stringList = (value: unknown): string[] | undefined =>
+  Array.isArray(value) ? value.filter((v): v is string => typeof v === 'string') : undefined;
+
+export function normalizeServerAcl(content: Record<string, unknown> | undefined): ServerAclContent {
+  if (!content) return { allow: ['*'], deny: [], allow_ip_literals: true };
+  return {
+    allow: stringList(content.allow) ?? [],
+    deny: stringList(content.deny) ?? [],
+    allow_ip_literals:
+      typeof content.allow_ip_literals === 'boolean' ? content.allow_ip_literals : true,
+  };
+}