feat: add atmos property to General entity and update related logic

- Added `atmos` property to the `General` interface in `entities.ts`.
- Initialized `atmos` to 0 in the `buildGeneralSeeds` function in `bootstrap.ts`.
- Updated exports in `index.ts` to include `unitSet.js`.
- Introduced new types for crew types and their requirements in `types.ts`.
- Implemented `unitSetLoader.ts` for loading unit set definitions from JSON files.
- Created `che_징병.ts` action for recruiting crew types with cost and training calculations.
- Developed `unitSet.ts` for handling crew type availability and requirements.
- Added tests for crew type availability and unit set parsing in `crewType.test.ts`.

app/game-engine/src/scenario/unitSetLoader.ts

@@ -0,0 +1,52 @@
+import fs from 'node:fs/promises';
+import path from 'node:path';
+import { fileURLToPath } from 'node:url';
+
+import { parseUnitSetDefinition, type UnitSetDefinition } from '@sammo-ts/logic';
+
+const __filename = fileURLToPath(import.meta.url);
+const __dirname = path.dirname(__filename);
+const DEFAULT_UNIT_SET_ROOT = path.resolve(
+    __dirname,
+    '..',
+    '..',
+    'resources',
+    'unitset'
+);
+
+export interface UnitSetLoaderOptions {
+    unitSetRoot?: string;
+    filePrefix?: string;
+}
+
+const readJsonFile = async (filePath: string): Promise<unknown> => {
+    const raw = await fs.readFile(filePath, 'utf8');
+    return JSON.parse(raw) as unknown;
+};
+
+const resolveUnitSetRoot = (options?: UnitSetLoaderOptions): string =>
+    options?.unitSetRoot ?? DEFAULT_UNIT_SET_ROOT;
+
+export const resolveUnitSetDefinitionPath = (
+    unitSetName: string,
+    options?: UnitSetLoaderOptions
+): string => {
+    const prefix = options?.filePrefix ?? 'unitset_';
+    return path.resolve(resolveUnitSetRoot(options), `${prefix}${unitSetName}.json`);
+};
+
+export const loadUnitSetDefinition = async (
+    unitSetPath: string
+): Promise<UnitSetDefinition> => {
+    const raw = await readJsonFile(unitSetPath);
+    return parseUnitSetDefinition(raw);
+};
+
+export const loadUnitSetDefinitionByName = async (
+    unitSetName: string,
+    options?: UnitSetLoaderOptions
+): Promise<UnitSetDefinition> => {
+    const unitSetPath = resolveUnitSetDefinitionPath(unitSetName, options);
+    return loadUnitSetDefinition(unitSetPath);
+};
+