pin: bump Worldtree spec 5810a26→879cefe (OpenAPI 2.2.0→2.3.0)

#347 authored-history-write shipped — one new REST path-group
POST /sessions/{id}/history + AuthoredTurnResponse schema. OpenAPI-only:
the prose conversation-api-spec.md + server conversation_api.contract.md
are byte-unchanged since 5810a26 (empty git-log delta), SSE schema
unchanged (#347 is event-silent). Consumer side NOT yet built —
POST /sessions/{id}/history is a fresh in-scope gap that re-opens the
v1 coverage-audit (Heimdall-gated hide-existence; 404 = feature-absent).

pyproject.toml

@@ -60,9 +60,9 @@ Repository = "https://gitea.phasefinal.com/vh/ratatoskr"
 # Ratatoskr is built against Worldtree at this commit; the vendored
 # spec snapshot in docs/ reflects that SHA.
 [tool.ratatoskr.spec-pin]
-worldtree-spec-rev = "5810a26b38a5ea6630892f9a39756f57c5b7b41e"
-worldtree-version = "v1.0.0b2"
-pinned-on = "2026-06-30"
+worldtree-spec-rev = "879cefef02bbf442c2d01ff4214299fac7c89809"
+worldtree-version = "v1.0.0b22"
+pinned-on = "2026-07-06"
 
 # Bifrost lives on the auth-gated gitea PyPI index (not public PyPI).
 # uv reads the credential from UV_INDEX_GITEA_USERNAME / _PASSWORD or ~/.netrc.