Fixes min-versions CI failure on `test-common / Minimum dependencies` – see https://github.com/canonical/craft-parts/actions/runs/36033223737/job/107746873946?pr=1659 **Root cause:** `lowest-python-platform: '["amd64", "focal"]'` selects a specific self-hosted focal runner that fails with `UV_RESOLUTION=lowest`: - `PermissionError: [Errno 1] Operation not permitted` in `test_write_overlay_migration_*` (mount --make-rprivate / fuse-overlayfs) - `OverlayStageConflict` in `test_overlay_must_not_collide` (layer-hides-file/dir) All are overlay/fuse related and only reproduce on that runner label. `["focal"]` (without `amd64`) still tests EOL 20.04 on the healthy self-hosted focal runner and passes – see `test-other-plugins / Minimum dependencies` success in same run, and `test-flaky / Minimum dependencies` success. **Fix:** keep focal (required for EOL base coverage per comment in qa.yaml) but drop `amd64`: - `test-common`: `'["amd64", "focal"]'` → `'["focal"]'` - `test-flaky`: `'["amd64", "focal"]'` → `'["focal"]'` - `test-other-plugins` already `'["focal"]'` – no change Adds FIXME comment linking failing run. **Not acceptable to switch to ubuntu-22.04** – we need to keep focal for chisel EOL testing (per user feedback). **Draft iteration:** all jobs except `test-common` temporarily `if: false` (`lint`, `test-flaky`, `test-java-plugins`, `test-python-plugins*`, `test-other-plugins`, `test-requires-root`) so only `test-common / Minimum dependencies (all tests)` on focal / py3.10 / lowest runs while iterating. Remove guards before merge. Verification: push triggers only `test-common`; check `Minimum dependencies (all tests)` on focal / py3.10 / UV_RESOLUTION=lowest passes.