yoda: re-apply hard rename — libcosmic → libcosmic-yoda (0.1.0-yoda)

Reverts the soft-fork pivot (6736a596). Strategy chosen with user:
full cascade fork. Every consumer (leyoda/cosmic-files + each leyoda/app)
depends on libcosmic-yoda by explicit path, so there are no transitive
deps left asking for the upstream 'libcosmic' crate — no [patch]
unification issues, no two-version traps.

Changes:
- Cargo.toml: name = libcosmic-yoda, version = 0.1.0-yoda
- i18n/*/libcosmic.ftl -> libcosmic_yoda.ftl (71 locales)
- examples/*/Cargo.toml dep refs back to libcosmic-yoda
- compat stub features (winit=[], x11=[]) kept for upstream deps that
  might still request them during the migration window

cargo check --lib passes.

examples/spin-button/Cargo.toml

@@ -6,7 +6,7 @@ edition = "2021"
 [dependencies]
 fraction = "0.15.3"
 
-[dependencies.libcosmic]
+[dependencies.libcosmic-yoda]
 features = ["debug", "wgpu", "winit", "desktop", "tokio"]
 path = "../.."
 default-features = false