Use Python 3.14(.3) in CI and base image (#6586)

* Use Python 3.14(.3) in CI and base image

Update base image to the latest tag using Python 3.14.3 and update Python
version in CI workflows to 3.14.

With Python 3.14, backports.zstd is no longer necessary as it's now available
in the standard library.

* Update wheels ABI in the wheels builder to cp314

* Use explicit Python fix version in GH actions

Specify explicitly Python 3.14.3, as the setup-python action otherwise default
to 3.14.2 when 3.14.3, leading to different version in CI and in production.

* Update Python version references in pyproject.toml

* Fix all ruff quoted-annotation (UP037) errors

* Revert unquoting of DBus types in tests and ignore UP037 where needed

tests/dbus/test_interface.py

@@ -28,12 +28,12 @@ class TestInterface(DBusServiceMock):
         self.object_path = object_path
 
     @signal(name="TestSignal")
-    def test_signal(self, value: str) -> "s":  # noqa: F821
+    def test_signal(self, value: str) -> "s":  # noqa: F821, UP037
         """Send test signal."""
         return value
 
     @dbus_property(access=PropertyAccess.READ, name="TestProp")
-    def test_prop(self) -> "u":  # noqa: F821
+    def test_prop(self) -> "u":  # noqa: F821, UP037
         """Get test property."""
         return 4
 

tests/utils/test_dbus.py

@@ -29,7 +29,7 @@ class TestInterface(DBusServiceMock):
     object_path = DBUS_OBJECT_BASE
 
     @method(name="Test")
-    def test(self, _: "b") -> None:  # noqa: F821
+    def test(self, _: "b") -> None:  # noqa: F821, UP037
         """Do Test method."""
 
     @signal(name="Test")