fix(client): include sideboard in the bracket-estimate cache key

[jeffrey701]

Problem

useBracketEstimate (client/src/hooks/useBracketEstimate.ts) derives a deckKey used both as the effect's short-circuit guard (if (deckKey === storedKeyRef.current) return;) and as the module cache key. But it was built from commanders + deck.main only:

const parts = [...commanders.map(...)];
for (const e of deck.main) parts.push(`m:${e.count}x${e.name...}`);

The estimate request itself, however, sends the sideboard too:

sideboard: deck.sideboard.flatMap((e) => Array(e.count).fill(e.name)),

So two decks identical in commanders + main but differing only in sideboard produced the same deckKey. The effect short-circuits and the cache returns the previous deck's estimate — a sideboard edit silently shows a stale bracket. The effect's own dependency comment even claimed sideboard "content is fully captured by deckKey", which was false.

Fix

Extract the key into a pure, unit-tested buildBracketDeckKey (client/src/hooks/bracketDeckKey.ts) that folds in the sideboard as well (s: parts). This makes the dependency comment true and keeps the sorted, order-independent behavior. Extraction is what lets the key be tested without standing up the debounced async hook.

Tests

Adds bracketDeckKey.test.ts: a sideboard-only difference now changes the key (fails before the fix — keys are equal); identical decks stay equal; ordering within main/sideboard doesn't matter; a main-deck change and a same-name main-vs-sideboard placement both change the key.

Self-contained: only useBracketEstimate.ts, a new pure helper, and its test; no engine/Rust/protocol changes.

Model: claude-opus-4-8

[gemini-code-assist]

Warning

You have reached your daily quota limit. Please wait up to 24 hours and I will start processing your requests again!