Fix config upgrade failures, save races, lock confirmation and release validation (#23)

* Coordinate config writes and gate releases on desktop validation

* Use toolkit rc.2 with painting and session lock fixes

* Ignore retired desktop widget settings in existing configs

shell/ferese-shell/Cargo.toml

@@ -18,7 +18,7 @@ libc.workspace = true
 # tiny-skia to avoid a second GPU initialization during desktop startup.
 libcosmic = { workspace = true, features = ["wgpu", "a11y"] }
 freedesktop-desktop-entry = { version = "0.8.3", default-features = false }
-iced_accessibility = { git = "https://github.com/ferese-wm/libcosmic", tag = "ferese-v0.1.3-rc.1" }
+iced_accessibility.workspace = true
 serde.workspace = true
 serde_json.workspace = true
 tempfile.workspace = true