Add profile peak daily fallback

[yvette-carlisle]

Summary

• fall back from profile peak_daily_tokens to the max daily_usage_buckets value when profile peak is missing
• keep Decodex App and operator dashboard account rows on the same peak display rule
• add Rust, Swift, and dashboard regression coverage

Verification

• cargo +nightly fmt --all -- --check
• git diff --check
• cargo test -p decodex profile_summary
• cargo test -p decodex operator_dashboard_accounts_keeps_compact_table_layout
• swift test --package-path apps/decodex-app
• apps/decodex-app/script/build_and_run.sh --verify