Validate sport type and improve plan_tour docs

- Add sport type validation against SupportedActivities
- List common sport types in docstring (racebike, touringbicycle, mtb, hike, jogging, mtb_easy)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: sebastianzabel

kompy/komoot_connector.py

@@ -344,7 +344,9 @@ def plan_tour(
         :param waypoints: List of waypoint dicts with 'lat' and 'lng' keys,
             e.g. [{'lat': 53.14, 'lng': 8.21}, ...]
         :param tour_name: Name of the planned tour
-        :param sport: Sport type, one of SupportedActivities (default: 'racebike')
+        :param sport: Sport type, one of SupportedActivities, e.g. 'racebike', 'touringbicycle',
+            'mtb', 'hike', 'jogging', 'mtb_easy' (gravel). See SupportedActivities for full list.
+            Default: 'racebike'
         :param constitution: Fitness level 1-5 (default: 3)
         :param date: ISO date string for the planned tour (default: now)
         :param status: Privacy status (default: PrivacyStatus.FRIENDS)
@@ -355,6 +357,12 @@ def plan_tour(
         if len(waypoints) < 2:
             raise ValueError('At least 2 waypoints are required to plan a tour.')
 
+        if sport not in SupportedActivities.list_all():
+            raise ValueError(
+                f'Invalid sport type: {sport}. '
+                f'Supported: {", ".join(SupportedActivities.list_all())}'
+            )
+
         if date is None:
             from datetime import datetime, timezone
             date = datetime.now(timezone.utc).strftime('%Y-%m-%dT%H:%M:%S.000Z')