feat(tests): add Jest+Supertest infrastructure with jump route suite (14 tests)

- Extract Express app creation into src/createApp.js to enable testing without starting the server
- Add Jest, Supertest, test helpers (createTestApp, auth token generator)
- Write 14 integration tests for skydive/jumps: auth protection, CRUD, ownership checks

Bugs caught and fixed by the test suite:
- MongoDB models: author field typed as Schema.Types.UUID (Mongoose 6 rejects string UUIDs) → changed to String
- Jump.toJSONFor: called toProfileJSONFor on a UUID string → guarded with typeof check
- exceptions.handler: used err.statusCode but express-jwt throws err.status → returns 500 on 401 errors
- Jump.count(query): deprecated Mongoose method was ignoring the filter → replaced with countDocuments
- jumps.routes GET /: $or query included non-schema field "title" stripped by strictQuery, leaving {} (match-all) → replaced with slug/lieu search
- $regex: was passing a JS RegExp object which serializes to {} in MongoDB → now passes raw string

src/createApp.js

@@ -0,0 +1,35 @@
+var express = require('express'),
+    session = require('express-session'),
+    cors = require('cors'),
+    errorhandler = require('errorhandler');
+
+const config = require('./config'),
+    swaggerUi = require('swagger-ui-express'),
+    swaggerSpec = require('./config/swagger');
+
+function createApp() {
+    const app = express();
+    app.use(cors());
+    app.use(express.json());
+    app.use(express.urlencoded({ extended: true }));
+    app.use(require('method-override')());
+    app.use(express.static(__dirname + '/../public'));
+    app.use(session({
+        secret: config.secret,
+        cookie: { maxAge: config.session_lifetime },
+        resave: false,
+        saveUninitialized: false
+    }));
+
+    if (process.env.APP_ENV !== 'production') {
+        app.use(errorhandler());
+    }
+
+    app.use('/api-docs', swaggerUi.serve, swaggerUi.setup(swaggerSpec, {
+        swaggerOptions: { persistAuthorization: true },
+    }));
+
+    return app;
+}
+
+module.exports = createApp;