feat(weather): OWM-Fallback über Server-.env wenn kein User-Key

Wetter-Proxy auf /api/weather/current nutzt optionalen Nutzer-Key aus
den Einstellungen, sonst OpenWeatherMapAPIKey aus der Umgebung.

Co-authored-by: Cursor <cursoragent@cursor.com>

server/src/index.ts

@@ -1,15 +1,21 @@
 import express from 'express'
 import cors from 'cors'
 import dotenv from 'dotenv'
+import { dirname, resolve } from 'node:path'
+import { fileURLToPath } from 'node:url'
 import authRouter from './routes/auth.js'
 import logbooksRouter from './routes/logbooks.js'
 import syncRouter from './routes/sync.js'
 import collaborationRouter from './routes/collaboration.js'
 import signRouter from './routes/sign.js'
 import pushRouter from './routes/push.js'
+import weatherRouter from './routes/weather.js'
 import { prisma } from './db.js'
 
-dotenv.config()
+const __dirname = dirname(fileURLToPath(import.meta.url))
+
+dotenv.config({ path: resolve(__dirname, '../../.env') })
+dotenv.config({ path: resolve(__dirname, '../.env') })
 
 const app = express()
 const PORT = process.env.PORT || 5000
@@ -24,6 +30,7 @@ app.use('/api/sync', syncRouter)
 app.use('/api/collaboration', collaborationRouter)
 app.use('/api/sign', signRouter)
 app.use('/api/push', pushRouter)
+app.use('/api/weather', weatherRouter)
 
 // Health check endpoint
 app.get('/api/health', async (req, res) => {