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/ui/dice-tray.hbs

@@ -0,0 +1,17 @@
+<div class="lf-dt-row">
+  <span class="lf-dt-label"><i class="fa-solid fa-dice"></i></span>
+  <select class="lf-dt-count" title="{{countTitle}}">
+    {{#each countOptions}}
+    <option value="{{this}}">{{this}}</option>
+    {{/each}}
+  </select>
+  <div class="lf-dt-dice">
+    {{#each diceButtons}}
+    <button type="button" class="lf-dt-die-btn" data-die="{{this.value}}" title="{{this.label}}">{{this.label}}</button>
+    {{/each}}
+  </div>
+  <label class="lf-dt-explode-label" title="{{explodeTitle}}">
+    <input type="checkbox" class="lf-dt-explode" />
+    <i class="fa-solid fa-explosion"></i>
+  </label>
+</div>