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>

tests/hub_case.py

@@ -136,8 +136,8 @@ class HubCase(unittest.TestCase):
         self.assertEqual(status, 200, body)
         return signer.proof(json.loads(body)["payload"], self.origin)
 
-    def board_proof(self, action: str, signer: Key) -> dict:
-        status, _, body = self.post_json("/api/board/sign", {"action": action}, self.guard(self.host))
+    def board_proof(self, action: str, signer: Key, agents: list[str] | None = None) -> dict:
+        status, _, body = self.post_json("/api/board/sign", {"action": action, **({} if agents is None else {"agents": agents})}, self.guard(self.host))
         self.assertEqual(status, 200, body)
         return signer.proof(json.loads(body)["payload"], self.origin)