refactor: extract inline HTML to templates, split oversized files, fix bugs

- Extract all inline HTML from JS into 21 Handlebars templates (chat/, dialogs/, ui/)
- Split utils.mjs (1507) into barrel + helpers.mjs, combat.mjs, d30.mjs
- Split roll.mjs (1632) into barrel + roll-base.mjs, roll-prompt.mjs, roll-combat.mjs, roll-damage.mjs
- Split lethal-fantasy.mjs (1426) into bootstrap + chat-reaction.mjs
- Fix: missing async on injectDiceTray (free-roll.mjs:29 SyntaxError)
- Fix: weapon._id fallback for deserialized chat-message weapon objects
- Fix: missing await on rollModifier.evaluate() calls in roll-combat.mjs
- Fix: choices→choicesList ReferenceError in utils.mjs
- Fix: add 12 missing i18n keys (chooseWeapon, chooseSave, attackRoll, etc.)
- Fix: restore sideLabel in bonus-die-select.hbs
- Clean: remove dead messageContent param, console.log→log()
- Style: barrel files preserve existing import paths

templates/dialogs/attack-grit.hbs

@@ -0,0 +1,8 @@
+<div class="grit-luck-dialog">
+  <div class="combat-status">
+    <p><strong>{{attackerName}}</strong> currently has <strong>{{currentAttackRollWithBonus}}</strong></p>
+    <p><strong>{{defenderName}}</strong> rolled <strong>{{defenseRoll}}</strong></p>
+    {{#if totalBonus}}<p class="bonus-info">Bonus already added: +{{totalBonus}}</p>{{/if}}
+  </div>
+  <p class="offer-text">You are losing! Spend Grit to add 1D6 to your attack?</p>
+</div>