Initial commit — Station 0 vertical slice in progress

Includes full design documentation (ARCHITECTURE, DESIGN_NOTES, CONTENT_SPEC, PRODUCTION_NOTES)
and active Godot 4 / GDScript codebase. Core systems built: player, floor generation,
room system, enemy base, body part upgrades, run manager, save system, HUD, EventBus.

scripts/upgrades/body_part_data.gd

@@ -0,0 +1,29 @@
+extends Resource
+class_name BodyPartData
+
+@export var slot:         String = ""   # "head" | "torso" | "left_arm" | "right_arm" | "legs"
+@export var display_name: String = ""
+
+# ---------------------------------------------------------------------------
+# Stat modifiers — additive bonuses stacked across all equipped parts.
+# Field names mirror the stat keys used in player_stats.gd.
+# ---------------------------------------------------------------------------
+@export var mod_speed:      float = 0.0
+@export var mod_max_health: float = 0.0
+@export var mod_damage:     float = 0.0
+@export var mod_fire_rate:  float = 0.0
+@export var mod_range:      float = 0.0
+@export var mod_proj_speed: float = 0.0   # flat delta; e.g. -104 = -20% of base 520
+
+# ---------------------------------------------------------------------------
+# Scatter (left arm slot)
+# mod_scatter_count > 0 enables multi-shot spread from this part
+# ---------------------------------------------------------------------------
+@export var mod_scatter_count:      int   = 0
+@export var mod_scatter_spread_deg: float = 0.0
+
+# ---------------------------------------------------------------------------
+# Shield Projector (left arm slot)
+# Active block on cooldown — absorbs one hit per activation
+# ---------------------------------------------------------------------------
+@export var shield_projector: bool = false