chore(promotion): promote dev to master for beta

[kattsushi]

Requested outcome

Prepare the reviewed dev integration state for a beta-channel promotion to master. Opening the PR is authorized; merging and publication require a separate explicit human authorization.

Immutable candidate

• dev: 1405889a92584c101b08f868b936e230c092d681
• current master: a9fe9bad94ab340da8a2b83cef0a2139861281fd
• master is an ancestor of dev
• 99 commits; 546 files; +22,083/-57,006

Expected beta effects on merge

All seven Nx release projects are affected:

• @effectify/react-router
• @effectify/react-query
• @effectify/node-better-auth
• @effectify/solid-query
• @effectify/react-router-better-auth
• @effectify/prisma
• @effectify/hatchet

A merge to master will run beta-only release processing and docs deployment. Stable publication remains manual-only and is out of scope.

Acceptance criteria before merge authorization

• Promotion PR CI passes on the exact candidate.
• Release policy contract confirms master→beta and manual stable separation.
• RR8 RETIRED status and exact 8.3.0 remain green.
• Reviewer verifies the aggregate promotion map and seven affected release projects.
• No auto-merge. No beta publication before explicit approval.

Review context

The aggregate promotion diff is a boundary exception; implementation was reviewed through 46 merged PRs on dev, including the bounded React Router consolidation chain and release-policy PR #223 and promotion-format PR #227 and prerelease-collision PR #229.