chore: clean public launch surface

[AlainDor]

Summary

• move public recovery benchmark assets to benchmarks/recovery and remove tracked scratch research fixtures
• rewrite README/STATUS, add docs index, launch readiness checklist, and launch posting plan
• scrub stale internal public references and fix transient quorum adapter ETXTBSY spawn flake

Verification

• cargo build --workspace
• cargo test --workspace
• cargo test --workspace --all-features
• cargo fmt --all -- --check
• cargo clippy --all-targets --all-features -- -D warnings
• cargo deny check
• cargo doc --workspace --no-deps
• cargo publish --dry-run -p mimir-core --allow-dirty
• cargo test -p mimir-harness --test recovery_benchmark
• python3 benchmarks/recovery/test_bench.py
• public-surface stale path sweep: no hits
• git ls-files research docs/research: no tracked files