IONOS: prepare v31 image — user_oidc v8.6.1, nc-config v31-57e335c, CI (HDNEXT-1969)

[printminion-co]

What

Preparation fixes for the HDNEXT-1969 sequential v31 image. Four commits:

1. user_oidc → v8.6.1 — bump apps-external/user_oidc from v7.0.0 (9bbc500) to v8.6.1 (b5a67c7).
2. config repo rename + reorder — point the IONOS submodule at the renamed nc-config repo (was easystorage-config) and move its .gitmodules entry to last.
3. config → v31-57e335c — bump the IONOS config submodule from 140d28ce to the v31-57e335c pre-release (57e335c).
4. CI make-target rename — update hidrive-next-build.yml to the new nc-config Makefile target names.

Why

• user_oidc: on ionos-dev-v31 the submodule still pointed at the original v31-era v7.0.0. The v30 history merged in for HDNEXT-1969 contained the v8.10.1 bump and the HDNEXT-1914 downgrade-to-v8.6.1 (restores LoginFlowV2 bearer auth), but the rc/web-3.5 merge resolved the submodule conflict to the wrong side and reverted it to v7.0.0. A full app-submodule sweep (ionos-dev vs v31) confirmed user_oidc was the only regressed app. This realigns v31 with the version shipped on ionos-dev.
• config repo rename: the config repository was renamed easystorage-config → nc-config; .gitmodules now uses the current url and lists the entry after the app pointers it references.
• config bump: brings in the v31-57e335c pre-release config (enables user_oidc bearer auth, UK→GB market rename, etc.) for the v31 image.
• CI rename: the v31-57e335c nc-config Makefile replaced the per-app build_dep_*_app targets with the dynamic apps-matrix naming (build_<app>_app). Without this the image build fails with No rule to make target 'build_dep_simplesettings_app'.

Test

• git -C apps-external/user_oidc describe --tags → v8.6.1
• git -C IONOS describe --tags → v31-57e335c
• .gitmodules: single [submodule "IONOS"], listed last, url nc-config.git
• git grep -n build_dep .github/workflows/hidrive-next-build.yml → no matches
• GitHub Actions build on this PR goes green; verify LoginFlowV2 / bearer-token OIDC login on the built v31 image.

Notes

• Deferred (separate effort): porting the full v33 matrix CI pipeline (prepare-matrix/build-apps + detect-app-cache.sh) to v31 with the ionos-dev-v* branch convention.