fix: fall back to latest git tag when .version file is missing

VERSION variable now resolves from git tags when VERSION_FROM_FILE
is empty, so version:resolve-next works on fresh checkouts without
a committed .version file.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: ChristophShyper

Taskfile.variables.yml

@@ -43,7 +43,12 @@ vars:
   VERSION:
     sh: |
       if [ "${VERSION_OVERRIDE}" = "__TAKEN_FROM_FILE__" ]; then
-        echo "{{.VERSION_FROM_FILE}}"
+        from_file="{{.VERSION_FROM_FILE}}"
+        if [ -n "$from_file" ]; then
+          echo "$from_file"
+        else
+          git tag --sort=-v:refname 2>/dev/null | grep -E '^v[0-9]+\.[0-9]+\.[0-9]+$' | head -1
+        fi
       else
         echo "${VERSION_OVERRIDE}"
       fi