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)

core/currency/README.md

@@ -0,0 +1,111 @@
+# Currency Module Documentation
+
+## Overview
+
+The `currency/` subfolder contains the data structure for defining in-game currencies.
+
+## Files
+
+### `currency.gd`
+
+Defines the `Currency` class - a Resource for currency metadata.
+
+## Currency Class
+
+```gdscript
+class_name Currency
+extends Resource
+
+@export var id: StringName = &""          # Unique identifier (e.g., &"gold")
+@export var display_name: String = ""     # UI-friendly name
+@export var icon: Texture2D               # Display icon
+```
+
+## Usage
+
+### Defining a Currency
+
+Create a `.tres` resource file with:
+- **id**: Lowercase unique key (used internally)
+- **display_name**: What players see ("Gold", "Gems")
+- **icon**: Texture for UI display
+
+Example `res://sandbox/currencies/gold.tres`:
+```
+[gd_resource type="Resource" script_class="Currency"]
+[resource]
+id = &"gold"
+display_name = "Gold"
+icon = ExtResource("uid://...")
+```
+
+### Accessing Currencies
+
+Currencies are defined in a `CurrencyCatalogue` resource that holds an array of `Currency` resources.
+
+```gdscript
+# Get all known currency IDs from the catalogue
+var ids: Array[StringName] = currency_catalogue.get_all_ids()
+
+# Get currency resource by ID
+var gold: Currency = currency_catalogue.get_currency_by_id(&"gold")
+```
+
+## Integration with LevelGameState
+
+Currencies are tracked in three ways:
+1. **current**: Current balance (resets on prestige)
+2. **total**: Total acquired this run (resets on prestige)
+3. **all_time**: Lifetime total (never resets)
+
+```gdscript
+# Add currency
+level_game_state.add_currency(gold_resource, BigNumber.new(100.0, 0))
+
+# Add by ID
+level_game_state.add_currency_by_id(&"gold", BigNumber.new(100.0, 0))
+
+# Get balance
+var balance: BigNumber = level_game_state.get_currency_amount_by_id(&"gold")
+
+# Spend currency (returns false if insufficient)
+var success: bool = level_game_state.spend_currency_by_id(&"gold", BigNumber.new(50.0, 0))
+
+# Check if currency exists
+var is_valid: bool = level_game_state.is_known_currency_id(&"gems")
+
+# Get currency resource
+var gold: Currency = level_game_state.get_currency_resource(&"gold")
+
+# Get display name
+var name: String = level_game_state.get_currency_name(&"gold")
+```
+
+## CurrencyCatalogue Class
+
+```gdscript
+class_name CurrencyCatalogue
+extends Resource
+
+@export var currencies: Array[Currency] = []
+
+func get_currency_by_id(id: StringName) -> Currency
+func get_all_ids() -> Array[StringName]
+```
+
+The `CurrencyCatalogue` is a resource that holds all defined currencies and is assigned to `LevelGameState` via the `currency_catalogue` export variable.
+
+## Signals
+
+`LevelGameState` emits `currency_changed(currency_id: StringName, new_amount: BigNumber)` whenever a currency balance changes.
+
+## See Also
+
+- `core/level_game_state.gd` - Currency state management
+- `core/big_number.gd` - Large number handling
+- `core/currency/currency_catalogue.gd` - Currency catalogue resource
+- `core/generator/currency_generator_data.gd` - Generator purchase currency
+
+</content>
+<parameter=filePath>
+/home/mikymod/work/jmp/idle/core/currency/README.md

core/currency/currency.gd

@@ -4,3 +4,4 @@ extends Resource
 @export var id: StringName = &""
 @export var display_name: String = ""
 @export var icon: Texture2D
+@export var always_visible: bool = false

core/currency/currency_catalogue.gd

@@ -0,0 +1,17 @@
+class_name CurrencyCatalogue
+extends Resource
+
+@export var currencies: Array[Currency] = []
+
+func get_currency_by_id(id: StringName) -> Currency:
+	for currency in currencies:
+		if currency.id == id:
+			return currency
+	return null
+	
+func get_all_ids() -> Array[StringName]:
+	var ids: Array[StringName] = []
+	for currency in currencies:
+		if currency.id != &"":
+			ids.append(currency.id)
+	return ids

core/currency/currency_catalogue.gd.uid

@@ -0,0 +1 @@
+uid://621tus0uvbrd

core/currency/currency_panel.gd

@@ -0,0 +1,35 @@
+## Dynamically displays all currencies from the LevelGameState catalogue as CurrencyTile widgets.
+class_name CurrencyPanel
+extends PanelContainer
+
+const CURRENCY_TILE_SCENE: PackedScene = preload("res://currency_tile.tscn")
+
+@onready var _tiles_container: VBoxContainer = $CurrencyTiles
+
+var _game_state: LevelGameState
+
+func _ready() -> void:
+	_game_state = find_parent("LevelGameState")
+	if _game_state == null:
+		push_error("CurrencyPanel: No LevelGameState found in parent hierarchy")
+		return
+	_build_currency_tiles()
+	_game_state.ready.connect(_on_game_state_ready)
+
+func _build_currency_tiles() -> void:
+	for child in _tiles_container.get_children():
+		child.queue_free()
+	
+	if _game_state.currency_catalogue == null:
+		return
+	
+	for currency in _game_state.currency_catalogue.currencies:
+		if currency == null:
+			continue
+		var tile: CurrencyTile = CURRENCY_TILE_SCENE.instantiate()
+		tile.currency = currency
+		tile.game_state = _game_state
+		_tiles_container.add_child(tile)
+
+func _on_game_state_ready() -> void:
+	pass

core/currency/currency_panel.gd.uid

@@ -0,0 +1 @@
+uid://blfou5xiynxqf