fix(hook): suppress peer list when daemon is unreachable

Fold daemonError into SessionAnnounceOptions so the helper owns the
mutually-exclusive choice between peer list and daemon-down hint. Before
this fix, a session-announce against an unreachable daemon emitted both
"No other mailboxes seen within the last 60 minutes (0 total registered)."
(misleading — the daemon was never asked) AND the daemon-unreachable hint.
Now only the hint appears when the daemon is down.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

node/src/cli.ts

@@ -260,8 +260,8 @@ program
       windowMinutes: opts.peerWindowMinutes,
       maxPeers: opts.maxPeers,
       watcherCommand: `claude-mailbox watch --block --name ${name}`,
+      daemonError: daemonError ?? undefined,
     });
-    if (daemonError) lines.push("", daemonError);
     lines.push("");
     process.stdout.write(lines.join("\n"));
   });

node/src/hook.ts

@@ -123,10 +123,11 @@ export interface SessionAnnounceOptions {
   windowMinutes: number;
   maxPeers: number;
   watcherCommand?: string;
+  daemonError?: string;
 }
 
 export function buildSessionAnnounceLines(opts: SessionAnnounceOptions): string[] {
-  const { name, peers, windowMinutes, maxPeers, watcherCommand } = opts;
+  const { name, peers, windowMinutes, maxPeers, watcherCommand, daemonError } = opts;
   const lines = [
     `Claude-Mailbox: your mailbox name this session is \`${name}\`.`,
     `The name is auto-derived as <project>-<session-short>. You can rename it (e.g. to tag your working area) with mcp__mailbox__rename(current_name="${name}", new_name="<project>-<area>-<short>"); after that, use the new name everywhere.`,
@@ -151,7 +152,11 @@ export function buildSessionAnnounceLines(opts: SessionAnnounceOptions): string[
       `    - exit code 2 → daemon unreachable; wait ~5 s, then relaunch.`,
     );
   }
-  lines.push("", ...formatActivePeerList(peers, name, { windowMinutes, maxPeers }));
+  if (daemonError) {
+    lines.push("", daemonError);
+  } else {
+    lines.push("", ...formatActivePeerList(peers, name, { windowMinutes, maxPeers }));
+  }
   return lines;
 }