Merge pull request 'pack: v0.38.1 — bnstoolkit 0.5.1 UI coords hotfix' (#77) from hotfix/bnstoolkit-ui-coords into main

Every screen positioned its child widgets with setPos(getX() + offset,
getY() + offset) under the assumption that FTB Library uses absolute
screen coordinates. It uses PARENT-RELATIVE coordinates — the panel's
own position is added back at render time — so all widgets rendered
at panel-position * 2 + offset, shoving them off the right edge.

Fix: drop the getX()/getY() from every setPos. Now using plain
parent-relative offsets, which is what FTB Library docs + FTB Quests/
Chunks source actually do.

Affects: HubScreen, TierUpgradeScreen, BountyBoardScreen,
PlotPurchaseScreen, ShopBrowserScreen, QuestLogScreen.
Also fixed BaseBnsScreen.contentTop()/contentBottom() to return
relative offsets.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

pack/pack.lock.json

@@ -1,13 +1,13 @@
 {
   "$schema": "Brass-and-Sigil pack.lock.json - generated, do not edit by hand unless you know what you are doing",
   "name": "Brass and Sigil",
-  "version": "0.38.0",
+  "version": "0.38.1",
   "minecraft": "1.21.1",
   "loader": {
     "type": "neoforge",
     "version": "21.1.228"
   },
-  "lockedAt": "2026-06-07T22:29:48Z",
+  "lockedAt": "2026-06-08T14:42:41Z",
   "mods": [
     {
       "source": "modrinth",