Add devenv to project

- Init devenv with node22 and corepack22
- Add devenv gitignore
- Direnv auto active devenv shell
- Update pnpm corepack version to 10.25.0
- Rerun pnpm install

Signed-off-by: Asai Neko <sugar@sne.moe>

.gitignore

@@ -33,3 +33,14 @@ pnpm-debug.log*
 !.yarn/releases
 !.yarn/sdks
 !.yarn/versions
+
+# Devenv
+.devenv*
+devenv.local.nix
+devenv.local.yaml
+
+# direnv
+.direnv
+
+# pre-commit
+.pre-commit-config.yaml