feat: Loksyu & TinJi standalone AppV2 apps with chat buttons and dice automation

- CDELoksyuApp: standalone HandlebarsApplicationMixin(ApplicationV2) app
  - 5-element Wu Xing grid with yin/yang inputs per element
  - Per-element reset buttons + global reset-all
  - Auto-refresh via updateActor hook

- CDETinjiApp: standalone AppV2 for the collective Tin Ji dice pool
  - Large neon counter with +/- buttons and direct input
  - Spend button sends a chat message with remaining count

- singletons.js: shared utilities
  - getSingletonActor: find or auto-create singleton actor
  - updateLoksyuFromRoll: compute lokAspect from Wu Xing cycle, update yin/yang
  - updateTinjiFromRoll: add tinji face count to value

- rolling.js: auto-update both singletons after every dice roll
  (weapon path + main roll path)

- system.js: renderChatLog hook injects Loksyu/TinJi footer buttons
  in the chat sidebar

- loksyu.js / tinji.js: actor sheets redirect to standalone apps
  when opened via the sidebar

- CSS: .cde-loksyu-standalone, .cde-tinji-standalone, .cde-chat-app-buttons,
  .cde-tinji-spend-msg styles added

- i18n: new keys in fr-cde.json and en-cde.json for all new UI strings
  (LoksyuNotFound, TinjiNotFound, Reset, ResetAll, SpendTinji, etc.)

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

src/ui/apps/singletons.js

@@ -0,0 +1,99 @@
+/**
+ * Singleton actor utilities for Loksyu and Tin Ji.
+ *
+ * Both are world-level shared trackers backed by a singleton Actor document
+ * of type "loksyu" / "tinji". GMs can create them via the Actors sidebar;
+ * the apps find the first one or offer to create it.
+ */
+
+import { ACTOR_TYPES } from "../../config/constants.js"
+
+/** Wu Xing generating cycle — [successes, auspicious, noxious, loksyu, tinji] */
+const WU_XING_CYCLE = {
+  wood:  ["wood",  "fire",  "water", "earth", "metal"],
+  fire:  ["fire",  "earth", "wood",  "metal", "water"],
+  earth: ["earth", "metal", "fire",  "water", "wood"],
+  metal: ["metal", "water", "earth", "wood",  "fire"],
+  water: ["water", "wood",  "metal", "fire",  "earth"],
+}
+
+/** Die face pairs [yin, yang] per aspect (0 = face "10") */
+const ASPECT_FACES = {
+  metal: [3, 8],
+  water: [1, 6],
+  earth: [0, 5],
+  fire:  [2, 7],
+  wood:  [4, 9],
+}
+
+/**
+ * Find the first actor of the given type in the world, or create one if the
+ * current user is a GM and none exists.
+ *
+ * @param {"loksyu"|"tinji"} type
+ * @returns {Promise<Actor|null>}
+ */
+export async function getSingletonActor(type) {
+  const existing = game.actors.find((a) => a.type === type)
+  if (existing) return existing
+
+  if (!game.user.isGM) {
+    ui.notifications.warn(game.i18n.localize(type === ACTOR_TYPES.loksyu ? "CDE.LoksyuNotFound" : "CDE.TinjiNotFound"))
+    return null
+  }
+
+  // Auto-create the singleton when the GM opens the app for the first time.
+  const nameKey = type === ACTOR_TYPES.loksyu ? "CDE.UpperCaseLoksyu" : "CDE.UpperCaseTinJi"
+  const actor = await Actor.create({
+    name: game.i18n.localize(nameKey),
+    type,
+    img: type === ACTOR_TYPES.loksyu
+      ? "systems/fvtt-chroniques-de-l-etrange/images/loksyu_long.webp"
+      : "systems/fvtt-chroniques-de-l-etrange/images/tinji.webp",
+  })
+  return actor ?? null
+}
+
+/**
+ * After a WuXing roll, add the loksyu faces (yin + yang) of the relevant
+ * aspect to the singleton Loksyu actor.
+ *
+ * @param {string} activeAspect  - The aspect used for the roll (e.g. "fire")
+ * @param {Object} faces         - Die face counts { 0: n, 1: n, …, 9: n }
+ */
+export async function updateLoksyuFromRoll(activeAspect, faces) {
+  const cycle = WU_XING_CYCLE[activeAspect]
+  if (!cycle) return
+
+  const lokAspect = cycle[3]
+  const [yinFace, yangFace] = ASPECT_FACES[lokAspect] ?? []
+  if (yinFace === undefined) return
+
+  const yinCount  = faces[yinFace]  ?? 0
+  const yangCount = faces[yangFace] ?? 0
+  if (yinCount === 0 && yangCount === 0) return
+
+  const actor = await getSingletonActor(ACTOR_TYPES.loksyu)
+  if (!actor) return
+
+  const current = actor.system[lokAspect] ?? { yin: { value: 0 }, yang: { value: 0 } }
+  await actor.update({
+    [`system.${lokAspect}.yin.value`]:  (current.yin.value  ?? 0) + yinCount,
+    [`system.${lokAspect}.yang.value`]: (current.yang.value ?? 0) + yangCount,
+  })
+}
+
+/**
+ * After a WuXing roll, add tinji faces to the singleton TinJi actor.
+ *
+ * @param {number} count - Number of tinji faces rolled
+ */
+export async function updateTinjiFromRoll(count) {
+  if (!count || count <= 0) return
+
+  const actor = await getSingletonActor(ACTOR_TYPES.tinji)
+  if (!actor) return
+
+  const current = actor.system.value ?? 0
+  await actor.update({ "system.value": current + count })
+}