Add Gitea Actions release workflow + combined VS Code build task

CI on push to master/main: cargo test, native arm64 build on the Pi5
runner, cross-compiled x64 build, rolling 'latest' release with both
binaries and checksums.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

.vscode/tasks.json

@@ -1,6 +1,16 @@
 {
   "version": "2.0.0",
   "tasks": [
+    {
+      "label": "Build alla (Linux + Windows)",
+      "type": "shell",
+      "command": "cargo build --release && cargo build --release --target x86_64-pc-windows-gnu && mkdir -p builds/linux/panels builds/win/panels && cp target/release/tui-wm builds/linux/tui-wm && cp target/x86_64-pc-windows-gnu/release/tui-wm.exe builds/win/tui-wm.exe && cp dist/linux/config.toml builds/linux/config.toml && cp dist/linux/panels/topbar.toml builds/linux/panels/topbar.toml && cp dist/win/config.toml builds/win/config.toml && cp dist/win/panels/topbar.toml builds/win/panels/topbar.toml && echo 'Done: builds/linux/tui-wm + builds/win/tui-wm.exe'",
+      "options": { "shell": { "executable": "bash", "args": ["-c"] } },
+      "group": "build",
+      "presentation": { "reveal": "always", "panel": "shared" },
+      "problemMatcher": ["$rustc"],
+      "detail": "Bygger båda binärerna: Linux (native) + Windows (kräver mingw-w64)"
+    },
     {
       "label": "Build (native)",
       "type": "shell",