feat: /api/data.php with fixture source, robots.txt

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

src/LiveSource.php

@@ -0,0 +1,29 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Weerscherm;
+
+/** Echte bronnen: Netatmo (stationsdata, regenmetingen) en Open-Meteo (verwachting). Wordt in fase 3/4 ingevuld. */
+final class LiveSource implements WeatherSource
+{
+    public static function fromConfig(Config $config): self
+    {
+        throw new \RuntimeException('LiveSource is nog niet beschikbaar; gebruik data_source = fixture');
+    }
+
+    public function stationsData(): array
+    {
+        throw new UpstreamException('niet geïmplementeerd');
+    }
+
+    public function measure(string $deviceId, string $moduleId, int $begin, int $end): array
+    {
+        throw new UpstreamException('niet geïmplementeerd');
+    }
+
+    public function forecast(float $lat, float $lon, string $timezone): array
+    {
+        throw new UpstreamException('niet geïmplementeerd');
+    }
+}