feat: Sprint 1 — backend fondations TetaRdPG

Auth SuperOAuth (JWT validation + httpOnly cookie), entités users/characters/level_thresholds,
lazy calculation endurance, seed 100 niveaux, config prod-ready (trust proxy, helmet, CORS, rate limit).
Validé : health 200, auth flow, character CRUD, endurance lazy, 401 sans cookie.

tsconfig.json

@@ -0,0 +1,21 @@
+{
+  "compilerOptions": {
+    "module": "commonjs",
+    "declaration": true,
+    "removeComments": true,
+    "emitDecoratorMetadata": true,
+    "experimentalDecorators": true,
+    "allowSyntheticDefaultImports": true,
+    "target": "ES2021",
+    "sourceMap": true,
+    "outDir": "./dist",
+    "baseUrl": "./",
+    "incremental": true,
+    "skipLibCheck": true,
+    "strictNullChecks": true,
+    "noImplicitAny": false,
+    "strictBindCallApply": false,
+    "forceConsistentCasingInFileNames": false,
+    "noFallthroughCasesInSwitch": false
+  }
+}