second to last commit hopefully final features and Ui refinements

firestore.rules

@@ -12,7 +12,7 @@ service cloud.firestore {
         request.resource.data.text is string &&
         request.resource.data.text.size() <= 240;
 
-      // the only update allowed is an echo 
+      // the only update allowed is an echo
       // echoCount and lastEchoAt fields can be changed
       // this prevents anyone from editing the text of someone else's message
       allow update: if
@@ -23,6 +23,27 @@ service cloud.firestore {
       allow delete: if false;
     }
 
+    // --- "passport stamps" --------------------------------------------------
+    // each anonymous-auth user has their own users/{uid}/stamps/{geohash4}
+    // subcollection (see firebase/stamps.js) - request.auth.uid == userId
+    // means a device can only ever read/write its OWN stamps, never anyone
+    // else's. Stamps are permanent once earned: no update/delete from the
+    // client, and create is validated the same way the messages create rule
+    // above validates its fields.
+    match /users/{userId}/stamps/{stampId} {
+      allow read: if request.auth != null && request.auth.uid == userId;
+
+      allow create: if
+        request.auth != null && request.auth.uid == userId &&
+        request.resource.data.keys().hasAll(['geohash4', 'city', 'country', 'iconId', 'color', 'earnedAt']) &&
+        request.resource.data.geohash4 is string &&
+        request.resource.data.city is string &&
+        request.resource.data.country is string;
+
+      allow update: if false;
+      allow delete: if false;
+    }
+
     // --- global "memory counter" (GlobalCountPill) -------------------------
     // a single shared doc, meta/stats, holding totalMessagesEverPosted.
     // anyone can read it (it's shown to every visitor); writes are limited to