Added explicit tests documenting that createCombatState, drawCards,
playCard, and endTurn all accept the original single-string/no-index
signatures and keep state.player and state.enemy aliases in sync.
startTurn resets energy/block for all players and draws 5 cards each,
also resets playersReady. resolveEnemyTurn iterates all enemies,
resets each enemy's block, and has each enemy act against player 0.
checkCombatEnd checks all enemies (victory) and any player (defeat).
Added tests and verified resolveEffects handles {type, index}
descriptors for multi-player and multi-enemy state. getEntity and
setEntity helpers resolve either legacy string keys or typed index
objects, so all existing string-based call sites continue working.
createCombatState now accepts arrays of characters and enemy IDs,
producing players[] and enemies[] arrays. Backward compat aliases
(state.player, state.enemy) are kept in sync. effects.js updated
to resolve entity descriptors as either legacy string keys or
{type, index} objects so both old and new call sites work.
Merged 120 watcher cards from watcher_cards.json into the unified
cards.json database, replacing the previous 8 stub entries. Deleted
watcher_cards.json since the data is now consolidated.
