CDNs found by themselves, and servers followed through time

PrivaPub now finds CDNs three ways, best first: the address ranges the
CDNs publish (Cloudflare, Fastly, Amazon CloudFront, Bunny, Gcore,
Imperva), downloaded daily by CdnUpdater and kept in CdnRangeSet; the
CDN's fingerprint in the responses it already gets from a server
(EdgeHintsHandler on the federation client); and the networks that carry
only a CDN. The fixed ASN list is gone; ASNs shared with plain hosting
(AWS, DataPacket) no longer hide a server. A server's Geo records the
CDN, its domain and how it was found, and weekly snapshots now keep the
city and coordinates too.

Servers through time (ServerPlaces): /instances/:host/history lists a
server's weekly snapshots, a CDN-fronted server's geo names the CDN's
domain and where the server was before it (before_cdn), and
/api/privapub/v1/cdns and /cdns/:domain group servers by CDN with week
by week who joined and who left. Owner decisions recorded in ROADMAP.

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

PrivaPub/Web/Pages/Stargazing.cshtml

@@ -14,7 +14,9 @@
 	only counted, through a key that is destroyed at the end of each day.</p>
 	<p>A server we exchange activities with is described once a week, from its public NodeInfo and, when it has one, its
 	Mastodon instance API. Its location comes from the address we reached, looked up in an offline database, and is shown
-	to the city; for a server behind a CDN, only the CDN is shown, since the address is the CDN's.</p>
+	to the city; for a server behind a CDN, only the CDN is shown, since the address is the CDN's. CDNs are recognised from
+	the address lists they publish and from their marks in the answers we get, and servers are grouped by their CDN week
+	by week.</p>
 	@if (Model.GeoSource is { } geo)
 	{
 		<p>Locations come from <a href="https://db-ip.com" rel="nofollow noopener">@geo</a>, licensed under