chore(release): 0.9.0

[nx10]

Bumps @styx-api/core and @styx-api/cli to 0.9.0 (cli pins core exactly), lockfile regenerated.

Minor rather than patch because three changes since 0.8.0 alter generated output:

• Give surviving anonymous structs a synthetic name #81 — surviving anonymous structs get a synthetic name
• Refactor the bindings dump into one uniquely-named tree #82 — bindings dump emits one uniquely-named tree
• perf(ir): flatten a sequence whose only meta is outputs #83 — IR flattens a sequence whose only meta is outputs

Also included since 0.8.0: repo rename styx-ts -> styx (#77, #79), playground UI modernization (#78), ESLint globals fix (#80).

Publish to npm via gh workflow run publish-npm.yml after merge.