unitysvc-sellers 0.3.16

Adds synchronous and asynchronous account-scoped room APIs for listing and reading rooms, posting messages, owner-written Markdown descriptions and settings, member listing, and invitation codes. New response metadata is optional when parsing older servers. Owner settings and member-list methods require the updated UnitySVC backend contract from commit 2338d1d6f.

Includes regenerated HTTP clients and room wire-contract regression tests.

Validation: 552 tests, lint, type checking, docs build, generated spec fingerprint and committed backend spec comparison pass.