drop the libqmi fork: Alpine's snapshot is past the !470 merge

Alpine's community/libqmi is at upstream 1c972b8a (2026-10-05), 23 commits
past the 30f3e998 this fork pinned "just past the !470 merge", with the
qmi-glib 1.39.1 the GNSS patches in modemmanager need. No patch was left;
the fork's one remaining addition, the FP6-tuned build (-march/-mtune,
whose gain was never measured), goes with it. build.sh loses its tarball,
checksum and build steps.

The registry still serves the fork (1.39.1_git20260808-r100 and -r101),
and that version outranks Alpine's 1.38.0_git* line, so with the aport
alone installed phones keep the fork and a fresh image takes it back at
its first 'apk upgrade': the fork's packages are deleted from the
registry with this push. Fresh images then install Alpine's libqmi and
keep it. Installed phones keep the fork until 'apk upgrade -a' downgrades
them to Alpine's or Alpine's version passes 1.39.1; the new modemmanager
works on either (verified on the FP6 with both).

pmbootstrap keeps a local package repository in its work dir and consults
it before every other repository. Whether that dir survives from one CI
run to the next is not established (run 60 rebuilt libqmi, modemmanager
and libcamera at the versions run 58 had built, which says it did not),
but nothing guarantees it either way, so build.sh deletes any
libqmi/qmi-utils apks found there before building, re-indexes the
repository from the files present and fails the run if any are left; the
publish step skips libqmi-*/qmi-utils-* as the backstop. pmbootstrap's
'zap --pkgs-local-mismatch' cannot do this: with systemd selected it looks
at packages/systemd-edge, not at the packages/edge the builds land in.

.forgejo/workflows/build.yml

@@ -52,14 +52,17 @@ jobs:
           path: dist/*
           if-no-files-found: error
 
-      # Ship every locally built apk (kernel, modemmanager, libqmi,
-      # callaudioshim, audio files, ...) to the Forgejo Alpine registry, so
+      # Ship every locally built apk (kernel, modemmanager, callaudioshim,
+      # audio files, ...) to the Forgejo Alpine registry, so
       # installed systems get updates via 'apk upgrade' instead of losing
       # the FP6 patches to the next upstream version bump. Requires the
       # PACKAGE_TOKEN repo secret (catbot account, package:write scope);
       # skips quietly until it exists. 409 = same version already published.
       # imsd and fingerprintd are skipped: build.sh 3b took them FROM the
       # registry (re-signed for the chroot), so they are not ours to publish.
+      # libqmi is skipped too: its fork was retired and deleted from the
+      # registry (2026-10-12); should a leftover apk ever sit in the runner's
+      # package dir, it must not bring the fork back.
       - name: Publish packages to the apk registry
         env:
           PACKAGE_TOKEN: ${{ secrets.PACKAGE_TOKEN }}
@@ -74,6 +77,7 @@ jobs:
             [ -e "$f" ] || continue
             case "$(basename "$f")" in
               imsd-*|fingerprintd-*) echo "registry-sourced, not republished: $(basename "$f")"; continue ;;
+              libqmi-*|qmi-utils-*) echo "retired fork, not republished: $(basename "$f")"; continue ;;
             esac
             found=1
             code=$(curl -s -o /dev/null -w '%{http_code}' \