fix(packaging): keep the per-commit version out of every module's cache key

flatpak-builder printed "Building module llvm" on every CI run instead
of "Cache hit". The build environment, CRAFTER_BUILD_VERSION included,
sat in the manifest's top-level build options, and those are part of
every module's cache key; the version changes with each commit, so no
module ever hit. Runs still took twelve minutes rather than eighty only
because ccache made the LLVM rebuild cheap.

The variables only matter to crafter-build's own module, so they move
there, and CI rewrites the version on that module. LLVM, the WASI
sysroot and wasmtime are now keyed on nothing that changes between
commits.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

.forgejo/workflows/ci.yaml

@@ -99,7 +99,7 @@ jobs:
           VERSION: ${{ steps.meta.outputs.version }}
         run: |
           set -eu
-          yq '."build-options".env.CRAFTER_BUILD_VERSION = strenv(VERSION)' "$MANIFEST" > "$CI_MANIFEST"
+          yq '(.modules[] | select(.name == "crafter-build") | ."build-options".env.CRAFTER_BUILD_VERSION) = strenv(VERSION)' "$MANIFEST" > "$CI_MANIFEST"
           grep -n 'CRAFTER_BUILD_VERSION' "$CI_MANIFEST"
           flatpak-builder --force-clean --ccache --disable-rofiles-fuse \
             --state-dir=/root/.cache/flatpak-builder \