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.

package.json

@@ -0,0 +1,41 @@
+{
+  "name": "tetardpg-backend",
+  "version": "0.1.0",
+  "description": "TetaRdPG backend — Auth + Characters + Endurance",
+  "scripts": {
+    "build": "nest build",
+    "start": "nest start",
+    "start:dev": "nest start --watch",
+    "start:prod": "node dist/main",
+    "seed": "ts-node -r tsconfig-paths/register src/database/seed.ts",
+    "typeorm": "typeorm-ts-node-commonjs -d src/database/data-source.ts"
+  },
+  "dependencies": {
+    "@nestjs/common": "^10.0.0",
+    "@nestjs/config": "^3.0.0",
+    "@nestjs/core": "^10.0.0",
+    "@nestjs/jwt": "^10.0.0",
+    "@nestjs/platform-express": "^10.0.0",
+    "@nestjs/throttler": "^5.0.0",
+    "@nestjs/typeorm": "^10.0.0",
+    "class-transformer": "^0.5.1",
+    "class-validator": "^0.14.0",
+    "cookie-parser": "^1.4.6",
+    "helmet": "^7.0.0",
+    "pg": "^8.11.0",
+    "reflect-metadata": "^0.2.0",
+    "rxjs": "^7.8.0",
+    "typeorm": "^0.3.20"
+  },
+  "devDependencies": {
+    "@nestjs/cli": "^10.0.0",
+    "@nestjs/schematics": "^10.0.0",
+    "@nestjs/testing": "^10.0.0",
+    "@types/cookie-parser": "^1.4.6",
+    "@types/express": "^4.17.21",
+    "@types/node": "^20.0.0",
+    "ts-node": "^10.9.1",
+    "tsconfig-paths": "^4.2.0",
+    "typescript": "^5.1.3"
+  }
+}