fix: add destroy() and signal cleanup across widgets, fix settings window + menu regressions

P0 leak fixes: context/action menus destroyed on deactivate, config
callbacks unregistered in settings widgets, recorder and server signal
IDs stored and disconnected, bluetooth client closed and unsubscribed,
rfkill timer removed, seek timers cancelled, dropdown and options menus
freed, app name cache LRU-bounded.

Fix desktop 'Edit Widgets' and settings menu regressions by deferring
destroy out of Gtk signal handlers via GLib.idle_add.

Fix settings entry fields by connecting the activate signal explicitly
(Enter saves the value).

src/utils/app_name_resolver.py

@@ -1,14 +1,18 @@
 import os
+from collections import OrderedDict
 
 
 class AppName:
+    _MAX_CACHE = 128
+
     def __init__(self, path="/usr/share/applications"):
         self.files = os.listdir(path)
         self.path = path
-        self._cache: dict[str, str | None] = {}
+        self._cache: OrderedDict[str, str | None] = OrderedDict()
 
     def get_app_name(self, wmclass, _format_=False):
         if wmclass in self._cache:
+            self._cache.move_to_end(wmclass)
             return self._cache[wmclass]
 
         desktop_file = ""
@@ -17,18 +21,22 @@ class AppName:
                 desktop_file = f
 
         if desktop_file == "":
-            self._cache[wmclass] = None
-            return None
+            result = None
+        else:
+            desktop_app_name = wmclass
+            with open(os.path.join(self.path, desktop_file)) as f:
+                lines = f.readlines()
+                for line in lines:
+                    if line.startswith("Name="):
+                        desktop_app_name = line.split("=")[1].strip()
+                        break
+            result = desktop_app_name
 
-        desktop_app_name = wmclass
-        with open(os.path.join(self.path, desktop_file)) as f:
-            lines = f.readlines()
-            for line in lines:
-                if line.startswith("Name="):
-                    desktop_app_name = line.split("=")[1].strip()
-                    break
-        self._cache[wmclass] = desktop_app_name
-        return desktop_app_name
+        self._cache[wmclass] = result
+        self._cache.move_to_end(wmclass)
+        if len(self._cache) > self._MAX_CACHE:
+            self._cache.popitem(last=False)
+        return result
 
     def format_app_name(self, title, wmclass, update=False):
         # Handle case when both title and wmclass are empty (no active window)