Make bare /quit disconnect only that server, keep windows open, bump to 0.1.9

/quit now disconnects the window's server without closing anything: every
buffer of that server and wIRC main get a "Disconnected" line, the server card
shows Disconnected with its Connect button, history is flushed to disk, and
there's no auto-reconnect. Connect rejoins the channels we were in (including
ones joined with /join, now tracked) into the still-open windows. Sending while
disconnected shows a "Not connected" line in that window. Exit wIRC still
disconnects everything and closes the app.

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

src/main/kotlin/data/AliasRepository.kt

@@ -50,6 +50,12 @@ object AliasRepository {
         return aliases.size
     }
 
+    /** True if [command] (without the leading '/') is an alias - those run locally, no server needed. */
+    fun hasAlias(command: String): Boolean {
+        val key = command.lowercase()
+        return key != RESERVED_RELOAD && key in aliases
+    }
+
     /**
      * Returns true if [command] (without the leading '/') matched a known alias and its
      * action was run - callers should treat that as "handled, don't fall through to IRC