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

module/documents/chat-message.mjs

@@ -13,7 +13,7 @@ export default class LethalFantasyChatMessage extends ChatMessage {
         messageData.isWhisper = false
         messageData.alias = this.user.name
       }
-      data.content = `<section class="dice-rolls">${rollHTML}</section>`
+      data.content = await foundry.applications.handlebars.renderTemplate("systems/fvtt-lethal-fantasy/templates/chat/dice-rolls.hbs", {rollHTML})
       return
     }