Require distinct panorama locations for rounds and captures

docs/panorama-contributions.md

@@ -2,6 +2,13 @@
 
 Maps hold 5–24 captured locations. Each game chooses five distinct locations in random order. The server plugin now picks random safe surface positions, with `viewpoints: 24` as the default for new installations; existing config files keep their value until edited and reloaded. The Fabric mod captures where the player is standing and permits up to 24 local captures; the uploader sends as many as the map and player limits allow.
 
+Round selection treats captures from the same block position as one location,
+even when their panorama IDs differ. Shared image paths are also selected only
+once. This applies to solo and multiplayer games, including older published maps.
+A map needs five distinct locations to start a game. The Fabric mod blocks
+another capture at an already captured block position and prevents captures
+while another capture or upload is in progress.
+
 ## Owner workflow
 
 Open the map in the dashboard. Under **Panorama settings**, enable **Allow players to add panoramas with you**. This is off by default. Share the map ID and its Minecraft X/Z bounds. Players must capture in the same world and inside those bounds. Owners can add their own captures using that map ID even when player contributions are disabled.