feat(client): trigger listening session creation after track + geolocation are available

[Rend1027]

Wait for both:

✅ Successful Spotify track fetch (currently or recently played)

✅ Successful geolocation via navigator.geolocation

Once both are available:

• Trigger POST /api/listening-sessions with payload:
  {
  "spotifyTrackId": "string",
  "title": "string",
  "artist": "string",
  "image_url": "string",
  "preview_url": "string",
  "lat": number,
  "lng": number
  }

• Confirm the backend returns a successful response (201 Created or success message)