* fix(presets): restore core skills instead of deleting them on preset remove
Skill restoration looked for core command templates under
.specify/templates/commands, a directory specify init never populates
in real projects. Since that lookup always missed, presets overriding
a core command (e.g. speckit.plan) had their skill deleted outright on
removal instead of restored — the actual core templates live in the
bundled core_pack (wheel install) or the repo-root templates/ tree.
Restoration now falls back to that bundled location, gated behind a
restore_from_bundled_core flag so the existing "retire a stale skill
superseded by a command-mode winner" path keeps deleting rather than
resurrecting a duplicate skill.
Fixes#3928
* fix(tests): use explicit utf-8 encoding reading restored skill content
read_text() defaults to the platform locale encoding, which is cp1252
("charmap") on Windows. The bundled specify.md core template contains a
UTF-8 multi-byte emoji whose bytes aren't valid cp1252, so the Windows CI
job failed decoding the restored SKILL.md with UnicodeDecodeError.
* fix(presets): keep extension restore priority over bundled-core fallback
The bundled-core fallback added for #3928 ran before the
extension_restore_index lookup, so a skill an installed extension owns
could be silently replaced by lower-priority bundled core content on
preset removal instead of preserving the extension's winning layer.
chelsealong
f4e3110560