Harden cross-cutting runtime contracts

[smiggleworth]

Summary

• scope resolved auth to each SSR render and preserve it through deferred streaming boundaries
• make successful superseded actions and mutations invalidate confirmed data while keeping visible state generation-safe
• coalesce queued query refreshes and fence reconciliation retries against newer work
• make horizontal roving focus direction-aware, repair range ownership transfer, preserve idle hydration with permanent skips, and centralize safe ref writes
• document the corrected SSR, data, hydration, and RTL behavior

Pattern audits

• audited all generation/controller comparisons in actions, mutations, queries, and reconciliation; they now use shared current-operation predicates
• audited render-context global fallbacks and context setters; low-level route resolution now transfers resolved auth into the request render context, including deferred passes
• audited renderer ref writes; mount, update, cleanup, and rollback use the canonical readonly-safe helper
• audited renderer range identity guards and hardcoded horizontal arrow handling in this package
• added overlapping async-cell tests, a concurrent deferred-auth test, an eight-cell hydration option matrix, a real RTL navigation test, and pathological readonly-ref coverage

Validation

• npm run fmt -- --check
• npm run lint
• npm run build
• npm test (238 unit, 37 checks, 1,498 jsdom, 52 browser)
• npm run test:types

No package versions, dependency ranges, release metadata, tags, or publish workflows were changed.

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