ci: derive binary version from git describe instead of a hardcoded string

main.go's version var now defaults to "dev" for local builds and is
overridden at build time via -ldflags "-X main.version=...". The
release workflow computes VERSION with `git describe --tags --always
--dirty` (fetch-depth: 0 so tags are available) and injects it into
the Go build inside the container.

.gitea/workflows/release.yml

@@ -26,11 +26,16 @@ jobs:
     steps:
       - name: Checkout
         uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
 
       - name: Build (${{ matrix.arch }})
         run: |
           set -o pipefail
 
+          VERSION="$(git describe --tags --always --dirty)"
+          echo "Version: $VERSION"
+
           # Crea il container senza avviarlo
           CID=$(docker create \
             --platform ${{ matrix.platform }} \
@@ -46,7 +51,7 @@ jobs:
           docker exec "$CID" sh -c "
             ${{ matrix.upx_install }}
             export CGO_ENABLED=0
-            go build -trimpath -ldflags='-s -w' -o /src/dist/todotxt2remind .
+            go build -trimpath -ldflags='-s -w -X main.version=$VERSION' -o /src/dist/todotxt2remind .
             upx /src/dist/todotxt2remind
           " 2>&1 | cat