feat(orchestrator): S5.2 drain, suspend and resume chosen agents

The Day/Night menu lists every claimed agent with a checkbox and an All box; Drain, Suspend and Resume act on the ticked agents only, are disabled when none is ticked, and the agent popup carries the same three buttons for that one agent. Each action is passkey-signed with its agent list, night.py takes --target per session and keeps a per-agent part, and each chosen agent gets a call naming the action and its skill. The night skills say how to read a per-agent night.

🎯 Fix: 90 %
💥 Break: 5 %
💸 Cost: 106 %
⏱️ Time: 100 %
🛡️ Security: 100 %
🏆 Score: 81
🚦 Gate: ⚠️ cost 106 % > 100: operator approved the commit

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

orchestrator/client/signing.py

@@ -135,8 +135,17 @@ def message_item(to: str, cls: str, text: str, upload: str, voice: str, voice_sh
     return {"kind": "message", "to": to, "class": cls, "text": text, "upload": upload, "voice": voice, "voice_sha256": voice_sha256}
 
 
-def board_item(action: str) -> dict:
-    return {"kind": "board", "action": action}
+def board_item(action: str, agents: list[str]) -> dict:
+    """Args:
+        action: the board action.
+        agents: the session ids a night action is limited to, sorted; empty
+            for every agent, which keeps the item of a board action without
+            agents unchanged.
+
+    Returns:
+        The item the operator's passkey signs.
+    """
+    return {"kind": "board", "action": action, **({"agents": agents} if agents else {})}
 
 
 def stream_item(origins: list[str], urls: list[str]) -> dict: