ci: move workflows to Gitea and add client release workflow

Move .github/workflows to .gitea/workflows with Gitea-compatible action
versions, fix make_tag outputs/major bump, and add release_clients.yml to
build and publish all clients to the Gitea package registries. Rename the Go
client module to git.warky.dev/wdevs and add LICENSE/CHANGELOG for Dart.

clients/resolvespec-dart/CHANGELOG.md

@@ -0,0 +1,5 @@
+# Changelog
+
+## 0.1.0
+
+- Initial release: ResolveSpec (JSON body) and FunctionSpec client.

clients/resolvespec-dart/LICENSE

@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2026 Hein
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.