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/chat/free-roll-card.hbs

@@ -0,0 +1,20 @@
+<div class="lf-free-roll-card">
+  <div class="lf-frc-header">
+    <i class="fa-solid fa-dice"></i>
+    <span class="lf-frc-title-text">{{titleText}}</span>
+    <span class="lf-frc-badge">{{badge}}</span>
+  </div>
+  <div class="lf-frc-dice">
+    {{#each dieChips}}
+    <div class="{{this.classes}}">
+      <span class="lf-frc-die-type">{{this.label}}</span>
+      <span class="lf-frc-die-sep">→</span>
+      <span class="lf-frc-die-val">{{this.value}}{{#if this.exploded}}<i class="fa-solid fa-burst lf-dt-explode-icon"></i>{{/if}}</span>
+    </div>
+    {{/each}}
+  </div>
+  <div class="lf-frc-total-bar">
+    <span class="lf-frc-total-label">{{totalLabel}}</span>
+    <span class="lf-frc-total-value">{{total}}</span>
+  </div>
+</div>