feat: use fenster ipc (sway/i3 compatible)

bar/services/fenster.py

@@ -0,0 +1,29 @@
+"""
+Fenster/Sway IPC connection helper.
+
+Provides a singleton I3 connection configured for Fenster's SWAYSOCK.
+"""
+
+import os
+from fabric.i3 import I3
+
+
+_connection: I3 | None = None
+
+
+def get_i3_connection() -> I3:
+    """Get the singleton I3 connection, configured for Fenster."""
+    global _connection
+    if _connection is None:
+        swaysock = os.environ.get("SWAYSOCK")
+        if swaysock:
+            I3.SOCKET_PATH = swaysock
+        elif not I3.SOCKET_PATH:
+            runtime_dir = os.environ.get(
+                "XDG_RUNTIME_DIR", f"/run/user/{os.getuid()}"
+            )
+            fallback = os.path.join(runtime_dir, "fenster.sock")
+            if os.path.exists(fallback):
+                I3.SOCKET_PATH = fallback
+        _connection = I3()
+    return _connection