Wire the client to PrivaPub: one sign-in, real feeds, a globe, nerd stats

One sign-in for both of PrivaPub's APIs: the root logs in on /clientapi,
picks a persona, and each persona gets its own Mastodon token in
exchange for the JWT (PersonaExchange). HttpService picks credentials
and JSON by route (JWT and camelCase for /clientapi, the persona token
and snake_case for /api, nothing for /oauth), retries a refused persona
token once, and records every request for the nerd stats.

The feed page is three columns: navigation with a persona switcher, the
feed with a tab per kind (home, local, federated, nearby, communities
and circles, direct, notifications, favourites, bookmarks, hashtags),
and a 3D globe that looks at the spherical mean of the posts in view
and draws a pulse and an arc to a hovered one. Posts sit at their own
place, their event's venue, the reader (located posts) or their
author's server as PrivaPub publishes it. Cards favourite, boost,
bookmark, reply, mute, block and delete; the composer posts with a
content warning, visibility, media and alt text, or as a located post.
Older pages load as the end nears; newer ones are polled while visible.
Nerd stats in tooltips: provenance, author and server, place, media,
counts, paging, the globe's camera and frame rate.

The mock (Faker, MessagesService, the Message models and store) and the
OIDC template leftovers are gone. Strings in English and Italian.

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

Services/MediaService.cs

@@ -0,0 +1,38 @@
+using System.Net;
+using System.Net.Http.Headers;
+
+using collAnon.Client.Services;
+
+using decePubClient.Extensions;
+using decePubClient.Models;
+using decePubClient.Models.Mastodon;
+
+using PrivaPub.ClientModels;
+
+namespace decePubClient.Services
+{
+	/// <summary>Uploads a picked file to PrivaPub (/api/v2/media, multipart) before the post that uses it.</summary>
+	public class MediaService(IHttpService httpService, CoalescingStringLocalizer localizer)
+	{
+		/// <summary>The uploaded attachment as Data; its id goes in the post's media_ids.</summary>
+		public async Task<WebResult> Upload(UploadMedia media, CancellationToken cancellationToken = default)
+		{
+			using var response = await httpService.Post(APIs.Mastodon.POST_Media, (Func<HttpContent>)(() =>
+			{
+				var file = new ByteArrayContent(media.Blob);
+				file.Headers.ContentType = MediaTypeHeaderValue.Parse(media.ContentType);
+				var content = new MultipartFormDataContent { { file, "file", media.FileName } };
+				if (media.AltText is { Length: > 0 } description)
+					content.Add(new StringContent(description), "description");
+				return content;
+			}), cancellationToken: cancellationToken);
+			if (!response.IsSuccessStatusCode)
+				return await response.Content.ReadWebResult(response.StatusCode, localizer, cancellationToken);
+
+			var attachment = await response.MastodonReadFromJsonAsync<MediaAttachment>(cancellationToken);
+			return attachment?.Id is null
+				? new WebResult().Invalidate(localizer["The server sent an invalid response."], (int)HttpStatusCode.BadGateway)
+				: new WebResult { Data = attachment };
+		}
+	}
+}