Archive noisy auto-approve/auto-merge workflows and add Review-Hub Alpha review docs

[DanFashauer]

Motivation

• Reduce risky automation blast radius by archiving auto-approve/auto-merge workflows during the controlled-demo/manual-review phase.
• Provide a clear public Alpha presentation surface so reviewers can evaluate positioning, demos, and roadmap without implying production readiness.
• Preserve Alpha engineering artifacts as an archive/reference while keeping Beta as the production-candidate path.

Description

• Move .github/workflows/auto-approve.yml and .github/workflows/auto-merge.yml into .github/workflows-disabled/ and add .github/workflows-disabled/README.md with restoration guidance and required pull_request/workflow_dispatch safeguards.
• Update docs/REPO_ENV_AUDIT_2026-03-31.md to record that the auto-approve/auto-merge workflows are archived and to require branch protection, labels, app permissions, and explicit inputs before restoration.
• Prepare SignalGrid-Review-Hub as the public Alpha review surface by adding README.md, docs/ALPHA_REVIEW_GUIDE.md, docs/ROADMAP_TO_BETA.md, and docs/REVIEW_CHECKLIST.md, and update the Review-Hub package.json name to signalgrid-review-hub.
• No runtime/product code or CI/build/test workflows (other than moving archived workflow YAMLs) were modified.
• Blocker: the Beta repository (DanFashauer/SignalGrid) could not be accessed from this environment, so requested Beta docs (REPO_LINEAGE, ALPHA_TO_BETA_PARITY, MILESTONE_STRATEGY, MOBILE_AND_PLATFORM_STRATEGY, INTEGRATION_CATALOG, CONFIG_PROFILE_ORCHESTRATION_STRATEGY, PARTNER_AND_ALLIANCE_STRATEGY) were not created here.

Testing

• In DEV: git diff --check completed with no issues.
• In DEV: npm run lint (via eslint) ran and completed successfully.
• In SignalGrid-Review-Hub: pnpm install --frozen-lockfile completed to provision dependencies.
• In SignalGrid-Review-Hub: pnpm run typecheck (TS tsc --build across the workspace) completed successfully.
• In SignalGrid-Review-Hub: initial pnpm run build failed due to missing env vars, and PORT=3000 BASE_PATH=/ pnpm run build succeeded.
• Blocker: git ls-remote https://github.com/DanFashauer/SignalGrid.git HEAD could not be completed here because the remote required credentials, preventing creation of the Beta docs in this run.

---

Codex Task