Replace expanded sequence arrays with compact descriptors

[JackWilb]

Summary

• publish a versioned compact sequence descriptor containing the config hash, deterministic seed, algorithm version, and sequence count
• derive only the assigned sequence row through a locked deterministic PRNG while preserving Latin-square, random, interruption, conditional, nested, and dynamic sequencing behavior
• continue loading legacy expanded sequence arrays and existing participant sessions without migration
• reject corrupt, unsupported, or config-mismatched descriptors with actionable recovery messages
• cover descriptor persistence through LocalStorage, Firebase, and Supabase

Impact

For library-calvi, the focused regression fixture measures:

• expanded sequence artifact: 3,350,322 bytes
• compact descriptor: 223 bytes
• reduction: greater than 99.99%

Concurrent publishers for the same config produce the same descriptor because version 1 derives its seed from the config hash.

Validation

• yarn install --frozen-lockfile
• yarn unittest --run (2,038 passed, 1 skipped)
• yarn typecheck
• yarn lint
• yarn build
• git diff --check

Playwright/browser profiling was not run. Before promoting this draft, the preview should be profiled in supported browsers to record download, parse/generation, and time-to-interactive changes for library-calvi.

Closes #1321

[github-actions]

A preview of 8693a42 is uploaded and can be seen here:

✨ https://revisit.dev/study/PR1369 ✨

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