chore(deps): adopt senpi 2026.9.15 and draft the beta.63 release notes

The pin moves 2026.9.13 -> 2026.9.15 across the six manifests and the four pin
assertions that guard them, and bun.lock is regenerated against the published
version.

provider-map.json only gets its header version: packages/ai/src/providers/all.ts
is byte-identical between v2026.9.13 and the release commit, so builtinProviders()
returns the same set and there is nothing to re-derive.

CHANGELOG [Unreleased] carries the beta.63 notes. They fold in two senpi releases,
not one: omo was pinned at 2026.9.13, so everything published as 2026.9.13-2 had
never reached an omo release note.