Update source files

crates/borders-core/src/game/constants.rs

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+/// Game constants organized by domain
+///
+/// This module centralizes all game balance constants that were previously
+/// scattered across multiple files. Constants are grouped by gameplay domain
+/// for easy discovery and tuning.
+pub mod combat {
+    /// Empire size balancing - prevents snowballing by large empires
+    /// Defense effectiveness decreases as empire grows beyond this threshold
+    pub const DEFENSE_DEBUFF_MIDPOINT: f32 = 150_000.0;
+
+    /// Rate of defense effectiveness decay for large empires
+    /// Uses natural log decay for smooth scaling
+    pub const DEFENSE_DEBUFF_DECAY_RATE: f32 = std::f32::consts::LN_2 / 50_000.0;
+
+    /// Base terrain magnitude cost for plains (baseline terrain)
+    /// Determines troop losses when conquering a tile
+    pub const BASE_MAG_PLAINS: f32 = 80.0;
+
+    /// Base terrain speed for plains (baseline terrain)
+    /// Affects how many tiles can be conquered per tick
+    pub const BASE_SPEED_PLAINS: f32 = 16.5;
+
+    /// Maximum random adjustment to border size when calculating expansion speed
+    /// Introduces natural variation in attack progression (0-4 range)
+    pub const BORDER_RANDOM_ADJUSTMENT_MAX: u32 = 5;
+
+    /// Multiplier for tiles conquered per tick when attacking unclaimed territory
+    pub const UNCLAIMED_TILES_PER_TICK_MULTIPLIER: f32 = 2.0;
+
+    /// Multiplier for tiles conquered per tick when attacking claimed territory
+    pub const CLAIMED_TILES_PER_TICK_MULTIPLIER: f32 = 3.0;
+
+    /// Large empire threshold for attack penalties (>100k tiles)
+    pub const LARGE_EMPIRE_THRESHOLD: usize = 100_000;
+
+    /// Random factor range for tile priority calculation (0-7)
+    pub const TILE_PRIORITY_RANDOM_MAX: u32 = 8;
+
+    /// Defense post magnitude multiplier (when implemented)
+    pub const DEFENSE_POST_MAG_MULTIPLIER: f32 = 5.0;
+
+    /// Defense post speed multiplier (when implemented)
+    pub const DEFENSE_POST_SPEED_MULTIPLIER: f32 = 3.0;
+}
+
+pub mod spawning {
+    /// Radius of tiles claimed around spawn point (creates 5x5 square)
+    pub const SPAWN_RADIUS: i32 = 2;
+}