Mirrors breadpad's proven pattern: ci/build.sh wraps bread-ecosystem's
shared ci/build.sh, pinned by commit sha in ci/bread-ecosystem.rev
(rev 147cfbbf96ae4b171027defa1130d2caddb934b1). No ci/deps.txt — the
shared image's gtk4/libadwaita/gtk4-layer-shell/graphene set already
covers breadhelp's dependency surface (no libadwaita or extra native
libs beyond those). dev-release.yml/rc-release.yml/release.yml now
build (and, in dev-release.yml, test) through ci/build.sh instead of
bare cargo on the runner; a new check.yml runs clippy+test on
feature/**/fix/** pushes as a fast pre-release signal.
Replaces the dev/beta branch split with one trunk (main): dev-track
builds still publish on every push, but the beta track now publishes
from a vX.Y.Z-rc.N prerelease tag instead of a separately-maintained
beta branch. Removes the branch nobody reliably kept in sync.
Adds bakery.toml (binaries, license_file, desktop_file, data_archive for
the guide content directory) and the standard three-track CI workflows,
mirroring the pattern used across the rest of the bread ecosystem.
Also fixes the tour/troubleshooting-symptoms loaders (tour.rs,
troubleshoot.rs) to check the bakery-writable user content root
(~/.local/share/breadhelp/content) before the system path a pacman
package would have used — the main ContentStore already did this via
user_content_root(), these two were the last holdouts still hardcoded to
/usr/share/breadhelp only.
