Add short enter aliases for Slack input

src/lazy_enter/bridge.py

@@ -18,7 +18,7 @@ logger = logging.getLogger(__name__)
 class Bridge:
     """Slack ↔ CLI 프로세스 간의 중계기."""
 
-    ENTER_COMMAND = "!enter"
+    ENTER_COMMANDS = {"!", "!e", "!enter"}
 
     def __init__(self, config: Config | None = None) -> None:
         self.config = config or Config()
@@ -45,7 +45,7 @@ class Bridge:
             self.slack.send_message(channel, ":warning: 연결된 세션이 없습니다.")
             return
 
-        if text.strip().lower() == self.ENTER_COMMAND:
+        if text.strip().lower() in self.ENTER_COMMANDS:
             self.pty.send_enter()
             self._last_sent_output = ""
             self._last_sent_fingerprint = None