feat(maestro): web spawn form stops naming sessions

The name field starts empty and the reroll is gone; the worktree branch keeps
a default by borrowing one handle from /api/names. A card whose name the
daemon generated renders dimmed until a first prompt settles it.

Refs #131

web/src/types.ts

@@ -292,6 +292,27 @@ export function customSessionName(s: Session): string | undefined {
   return undefined;
 }
 
+/** Where a session's name came from (#131). Mirrors
+ * `maestro_protocol::NameSource`. */
+export type NameSource = "User" | "Generated" | "Haiku";
+
+/** Read `metadata.name_source`, leniently: anything unrecognised — including
+ * a session named before the field existed — is a settled `User` name, so an
+ * existing name is never dimmed or overwritten. */
+export function nameSource(s: Session): NameSource {
+  const meta = s.metadata as Record<string, unknown>;
+  const source = meta?.name_source;
+  if (source === "Generated" || source === "Haiku") return source;
+  return "User";
+}
+
+/** Whether line 1 renders the name as provisional (#131): a handle the daemon
+ * generated at spawn and may still replace with one derived from the first
+ * prompt. See docs/SIDEBAR.md. */
+export function isProvisionalName(s: Session): boolean {
+  return customSessionName(s) !== undefined && nameSource(s) === "Generated";
+}
+
 /** Longest session name the daemon stores (#125), in characters. Mirrors
  * `maestro_protocol::MAX_SESSION_NAME_LEN`. */
 export const MAX_SESSION_NAME_LEN = 64;