Introduce `--profile expanded` to init compatibly with 1.1.x

[robberphex]

The default global profile is core, which includes propose, explore, apply, and archive. You can enable the expanded workflow commands with openspec config profile and then openspec update.

It breaks workflow which starts with /opsx:new.

The solution is use custom profile, but

1. It cannot finished in cli. It need to modify user-scope config file, which is volatile( by other command).
2. It need to wirte $HOME/.config/openspec/config.json file, but sometime those directory is not writable.

So we should have a simple way to keep compatiblity.

We introduce openspec init --profile expanded, it init with all commands same with 1.1.x version.
expanded is a built-in profile.