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/ad-hoc-shield.hbs

@@ -0,0 +1,18 @@
+<div class="grit-luck-dialog">
+  <div class="combat-status">
+    <p><strong>{{defenderName}}</strong> uses a shield (not equipped)</p>
+    <p>{{localize "LETHALFANTASY.Combat.attackRoll"}}: <strong>{{attackRoll}}</strong> — {{localize "LETHALFANTASY.Combat.currentDefense"}}: <strong>{{defenseRoll}}</strong></p>
+  </div>
+  <div class="weapon-selection" style="margin-top:8px;">
+    <label for="shield-dice">{{localize "LETHALFANTASY.Combat.shieldDice"}}:</label>
+    <select id="shield-dice" name="shieldDice" style="width: 100%; margin-top: 4px;">
+      {{#each choices}}
+      <option value="{{this}}">{{this}}</option>
+      {{/each}}
+    </select>
+  </div>
+  <div class="weapon-selection" style="margin-top:8px;">
+    <label for="shield-dr">{{localize "LETHALFANTASY.Combat.shieldDR"}}:</label>
+    <input id="shield-dr" name="shieldDR" type="number" min="0" value="0" style="width: 100%; margin-top: 4px;" />
+  </div>
+</div>