phase 1: refactor directory structure (value-objects, factions, characters)

src/value-objects/Level.ts

@@ -0,0 +1,34 @@
+/**
+ * Level value object — constrained to 1..10.
+ *
+ * "I can't believe it's not Haskell": invalid states are unrepresentable.
+ * Level progression (next) and combat modifiers (diff) belong to later stories.
+ */
+export class Level {
+  #value: number;
+
+  private constructor(n: number) {
+    this.#value = n;
+  }
+
+  static create(n: number): Level {
+    if (n < 1 || n > 10) {
+      throw new Error(`Level must be between 1 and 10, got ${n}`);
+    }
+    return new Level(n);
+  }
+
+  get value(): number {
+    return this.#value;
+  }
+
+  /** Maximum health for this level: 1000 until level 6, 1500 from level 6 onward. */
+  static maxHealthForLevel(level: number): number {
+    return level >= 6 ? 1500 : 1000;
+  }
+
+  /** Signed level difference: this level minus target level. Positive = this is higher. */
+  diff(target: Level): number {
+    return this.value - target.value;
+  }
+}