* refactor(config): remove legacy gcal top-level config key
Problem: the gcal migration shim silently accepted vim.g.pending = { gcal
= {...} } and copied it to sync.gcal, adding complexity and a deprecated
API surface.
Solution: remove the migration block in config.get(), drop the cfg.gcal
fallback in gcal_config(), delete the two migration tests, and clean up
the vimdoc references. Callers must now use sync.gcal directly.
* ci: fix
* fix(spec): remove duplicate buffer require in complete_spec