Restructure into core/ and content/official/

game/core/modding/mod_registry.gd

@@ -0,0 +1,92 @@
+extends Node
+
+## Loads modifier definitions and serves them by id.
+##
+## ⚠️ PROTOTYPE. This is scaffolding, not the real mod loader.
+##
+## What's wrong with it, to be fixed in Phase 3:
+##   - DirAccess cannot walk into a PCK. This works in the editor and silently
+##     returns NOTHING in an exported build. Needs a build-time manifest.
+##   - No namespacing. Ids are bare strings, so two mods can collide.
+##   - No mod.json, no api_version, no dependency resolution.
+##   - Only reads content/official/. Doesn't touch user://mods/.
+##
+## Autoload name is ModRegistry (PascalCase), so call sites read as
+## ModRegistry.get_by_id(...) rather than looking like a local variable.
+
+const MODIFIER_DIR := "res://content/official/modifiers/"
+
+var modifiers: Array[Modifier] = []
+var _by_id: Dictionary = {}
+
+
+func _ready() -> void:
+	_load_from_folder(MODIFIER_DIR)
+	_reindex()
+	print("ModRegistry: loaded %d modifiers." % modifiers.size())
+
+
+## Recursive, because each modifier now lives in its own folder:
+##   modifiers/mjolnir/mjolnir.tres
+func _load_from_folder(path: String) -> void:
+	var dir := DirAccess.open(path)
+	if dir == null:
+		push_warning("ModRegistry: can't open %s" % path)
+		return
+
+	dir.list_dir_begin()
+	var fname := dir.get_next()
+	while fname != "":
+		var full := path.path_join(fname)
+		if dir.current_is_dir():
+			if not fname.begins_with("."):
+				_load_from_folder(full)
+		elif fname.ends_with(".tres"):
+			var res := load(full)
+			if res is Modifier:
+				modifiers.append(res)
+			else:
+				push_warning("ModRegistry: %s is not a Modifier" % full)
+		fname = dir.get_next()
+	dir.list_dir_end()
+
+
+func _reindex() -> void:
+	_by_id.clear()
+	for m in modifiers:
+		if m.id.is_empty():
+			push_warning("ModRegistry: modifier with empty id, skipping.")
+			continue
+		if _by_id.has(m.id):
+			push_warning("ModRegistry: duplicate id '%s'." % m.id)
+		_by_id[m.id] = m
+
+
+func get_by_id(id: String) -> Modifier:
+	return _by_id.get(id)
+
+
+## Pick `count` distinct modifiers, weighted by rarity.
+func pick_random(count: int) -> Array[Modifier]:
+	var pool := modifiers.duplicate()
+	var chosen: Array[Modifier] = []
+	count = mini(count, pool.size())
+
+	for _i in count:
+		var total := 0.0
+		for m in pool:
+			total += maxf(m.weight, 0.0001)
+
+		var r := randf() * total
+		var acc := 0.0
+		var picked := 0
+		for j in pool.size():
+			acc += maxf(pool[j].weight, 0.0001)
+			if r <= acc:
+				picked = j
+				break
+
+		chosen.append(pool[picked])
+		pool.remove_at(picked)   # distinct — don't offer the same one twice
+
+	return chosen

game/core/modding/mod_registry.gd.uid

@@ -0,0 +1 @@
+uid://btm4dwci50xmu

game/core/modding/modifier.gd

@@ -0,0 +1,40 @@
+extends Resource
+class_name Modifier
+# One modifier definition: title + description + texture + scoring rule.
+# Create instances of this as .tres files in the editor (right-click in
+# FileSystem -> New Resource -> Modifier), OR build them in code in the catalog.
+#
+# Because a texture always maps to the same modifier, the texture lives HERE.
+
+# A stable unique id (e.g. "stars_x5"). Useful for saving which modifiers are
+# applied to which segments, and for lookups. Keep it unique across the catalog.
+@export var id: String = ""
+
+# Shown to the player when offered the piece.
+@export var title: String = ""
+@export_multiline var description: String = ""
+
+# The texture painted onto the segment when this modifier is applied.
+@export var texture: Texture2D
+
+# --- Scoring rule ---
+# Simple, data-only rules cover most cases without writing code per modifier.
+# value = (base_value * mult + add) for the affected segment.
+@export var score_mult: float = 1.0
+@export var score_add: int = 0
+
+# Optional: rarity weight for random selection (higher = more common).
+@export var weight: float = 1.0
+
+# Apply this modifier's rule to a segment's base value.
+func apply_score(base_value: int) -> int:
+	return int(round(base_value * score_mult)) + score_add
+
+# A short human-readable summary of the effect, for tooltips/UI.
+func effect_text() -> String:
+	var parts: Array[String] = []
+	if score_mult != 1.0:
+		parts.append("x%s" % str(score_mult))
+	if score_add != 0:
+		parts.append(("+%d" % score_add) if score_add > 0 else str(score_add))
+	return " ".join(parts) if parts.size() > 0 else "no change"

game/core/modding/modifier.gd.uid

@@ -0,0 +1 @@
+uid://duh0lxb7gdimr