Add distro/ubuntuCore for UC26 snap and image builds.

Centralize salmanoff snapcraft, dangerous-model image scripts, and QEMU
workflow so UC26 can be reproduced from the SMO repo without ubuntu-core-practice.

Co-authored-by: Cursor <cursoragent@cursor.com>

distro/ubuntuCore/.gitignore

@@ -0,0 +1,30 @@
+# Image build outputs (large)
+artifacts/images/
+artifacts/images-dev/
+artifacts/logs/
+
+# ubuntu-image scratch
+work/ubuntu-image-snap/
+work/ubuntu-image-dev/
+
+# Dev signing outputs (account-specific)
+models/salmanoff-dev-amd64.model
+models/ubuntu-core-26-amd64.model
+assertions/
+config/dev-image.env
+config/ssh/smo-dev
+config/ssh/smo-dev.pub
+
+# QEMU writable UEFI vars
+artifacts/firmware/OVMF_VARS_4M.ms.fd
+
+# snapcraft working tree
+snaps/salmanoff/parts/
+snaps/salmanoff/stage/
+snaps/salmanoff/prime/
+snaps/salmanoff/.snapcraft/
+snaps/salmanoff/*.snap
+
+# Editor / OS noise
+*~
+.DS_Store