systems rework: buffs, prestige graph, research, modular architecture

Decouples core systems from centralized globals in favor of catalogue-based architecture and data-driven content.

   Key changes:
   - Prestige: node-based buff tech tree, graph panel, progress bar
   - Research: multi-worker system, per-generator research, xp generation
   - Ascension: meta-currency layer via multi-currency prestige resets
   - Buffs: refactored as generator-independent via catalogues
   - UI: currency panel, edge-scrolling camera + zoom, current-goal panel
   - Alchemy Tower: crafting building with recipe/cost system
   - Testing: 7 test suites (ascension, prestige, research, goals)
   - Content: migrated from hardcoded idles/ to gym format (tiny_sword)

currency_tile.tscn

@@ -1,15 +1,17 @@
 [gd_scene format=3 uid="uid://btkxru2gdjsgc"]
 
 [ext_resource type="Script" uid="uid://sp67wcb6s5nw" path="res://currency_label.gd" id="1_0hv07"]
+[ext_resource type="Texture2D" uid="uid://d3nymghus6x3" path="res://sandbox/tiny_swords/UI Elements/UI Elements/Icons/Icon_03.png" id="2_otq0d"]
 
 [node name="CurrencyTile" type="HBoxContainer" unique_id=1440583137]
 theme_override_constants/separation = 12
 script = ExtResource("1_0hv07")
 
 [node name="CurrencyIcon" type="TextureRect" parent="." unique_id=935299369]
-visible = false
 custom_minimum_size = Vector2(20, 20)
 layout_mode = 2
+texture = ExtResource("2_otq0d")
+expand_mode = 2
 stretch_mode = 5
 
 [node name="Label" type="Label" parent="." unique_id=89234840]