Pixelfed places: a remote post's own place, shown and never federated again

A Note's `location` that is a Place with coordinates (Pixelfed sends
them as strings) is kept in the new Post.Place and shown as
Status.privapub.place {name, latitude, longitude, country}; an edit
replaces it. An Event's location stays its own `places`, and nothing
renders a place back out. Closes the INTEROP P2 Pixelfed location gap
and the ROADMAP long-tail item.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01LsXgEaXee4GCU1hwYgPJXw

PrivaPub.Tests/Federation/ObjectShapesTests.cs

@@ -1,4 +1,4 @@
-using PrivaPub.Api.Mastodon.Mappers;
+using PrivaPub.Api.Mastodon.Mappers;
 using PrivaPub.Federation.Objects;
 using PrivaPub.Models.Post;
 
@@ -79,6 +79,51 @@ namespace PrivaPub.Tests.Federation
 			Assert.Equal("2026-10-03 10:00 – 13:00 (Europe/Rome) · Biblioteca", MastodonMapper.EventLine(note.Event));
 		}
 
+		[Fact]
+		public void Keeps_a_pixelfed_place_whose_coordinates_are_strings()
+		{
+			var note = Parse("""
+				{
+					"id": "https://pixel.example/p/ann/1", "type": "Note", "attributedTo": "https://pixel.example/users/ann", "content": "<p>view</p>",
+					"location": { "type": "Place", "name": "Tokyo", "longitude": "139.6917", "latitude": "35.6895", "country": "Japan" },
+					"commentsEnabled": true
+				}
+				""");
+
+			Assert.Equal(("Tokyo", 35.6895, 139.6917, "Japan"), (note.Place.Name, note.Place.Latitude, note.Place.Longitude, note.Place.Country));
+			Assert.Null(note.Event);
+		}
+
+		[Theory]
+		[InlineData("null")]
+		[InlineData("""{ "type": "Place", "name": "Nowhere" }""")]
+		[InlineData("""{ "type": "Place", "name": "Off the map", "latitude": 123, "longitude": 9 }""")]
+		[InlineData("""{ "type": "Place", "latitude": "north", "longitude": "9.19" }""")]
+		[InlineData("""{ "type": "VirtualLocation", "url": "https://meet.example/a", "latitude": 45, "longitude": 9 }""")]
+		public void Has_no_place_without_a_place_with_coordinates(string location)
+		{
+			var note = Parse($$"""
+				{ "id": "https://pixel.example/p/ann/2", "type": "Note", "attributedTo": "https://pixel.example/users/ann", "content": "<p>x</p>", "location": {{location}} }
+				""");
+
+			Assert.Null(note.Place);
+		}
+
+		[Fact]
+		public void An_events_location_stays_the_events_own()
+		{
+			var note = Parse("""
+				{
+					"id": "https://events.example/events/10", "type": "Event", "name": "Picnic", "startTime": "2026-10-03T10:00:00+02:00",
+					"location": { "type": "Place", "name": "Park", "latitude": 45.07, "longitude": 7.68 },
+					"attributedTo": "https://events.example/@club"
+				}
+				""");
+
+			Assert.Null(note.Place);
+			Assert.Equal("Park", Assert.Single(note.Event.Places).Name);
+		}
+
 		[Fact]
 		public void Keeps_a_lemmy_link_post_as_a_link_with_its_thumbnail()
 		{