Add release docs and addon validation workflow

.github/workflows/validate-addon.yml

@@ -0,0 +1,43 @@
+name: Validate Addon
+
+on:
+  pull_request:
+  push:
+    branches:
+      - "**"
+
+jobs:
+  validate-addon:
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Check out source
+        uses: actions/checkout@v4
+
+      - name: Validate plugin.cfg semver
+        run: |
+          version="$(sed -n 's/^version="\(.*\)"$/\1/p' addons/godotdev_nvim_node_copy/plugin.cfg)"
+          if [ -z "$version" ]; then
+            echo "Could not read version from plugin.cfg" >&2
+            exit 1
+          fi
+
+          case "$version" in
+            [0-9]*.[0-9]*.[0-9]*)
+              ;;
+            *)
+              echo "plugin.cfg version '$version' is not valid semver" >&2
+              exit 1
+              ;;
+          esac
+
+      - name: Build release payload layout
+        run: |
+          mkdir -p dist/addons
+          cp -R addons/godotdev_nvim_node_copy dist/addons/
+          test -f dist/addons/godotdev_nvim_node_copy/plugin.cfg
+          test -f dist/addons/godotdev_nvim_node_copy/plugin.gd
+          test -f dist/addons/godotdev_nvim_node_copy/README.md
+          cd dist
+          zip -r addon.zip addons
+

README.md

@@ -210,3 +210,7 @@ To use `neovim_remote` mode:
 - Support `%UniqueNode` when appropriate
 - Add C# snippet variants
 - Let users choose snippet style in plugin settings
+
+## Releasing
+
+Release steps are documented in [RELEASING.md](RELEASING.md).

RELEASING.md

@@ -0,0 +1,36 @@
+# Releasing
+
+This repository uses the version in `addons/godotdev_nvim_node_copy/plugin.cfg`
+as the release version that Godot users will see after installing from GitHub or
+the Asset Library.
+
+## Release flow
+
+1. Make sure your working tree is clean.
+2. Run `./scripts/prepare-release.sh 0.3.1` or `./scripts/prepare-release.sh 0.3.1 --push`.
+3. If you did not use `--push`, push the branch and the tag:
+   - `git push origin <branch>`
+   - `git push origin v0.3.1`
+4. Wait for GitHub Actions to run `Package Release`.
+5. Verify the GitHub release contains `godotdev_nvim_node_copy-0.3.1.zip`.
+
+## What the script does
+
+- updates `plugin.cfg`
+- creates a release commit
+- creates a `vX.Y.Z` tag
+- optionally pushes the branch and tag
+
+## Safety checks
+
+- `scripts/prepare-release.sh` refuses to run with a dirty working tree.
+- `Package Release` fails if `plugin.cfg` does not match the tag version.
+- `Validate Addon` checks semver formatting and the packaged addon layout on push
+  and pull request.
+
+## Example
+
+```bash
+./scripts/prepare-release.sh 0.3.1 --push
+```
+