[Alts] Server-side search controls, IP counts, adjustable window

Plumbs the match-type chips through to the server: include_email/include_clientid/include_ip skip disabled identifier types in both matching and frontier expansion, so excluded types (e.g. throwaway domains) never enter the graph at any depth. Session lookback becomes adjustable (session_months, clamped 1-24, default 6). Each alt row carries ip_count, the distinct recent session IP count shown in a new IPs column. All proto additions are optional with old defaults, so old clients/servers interoperate.

libcockatrice_protocol/libcockatrice/protocol/pb/serverinfo_user_alt.proto

@@ -17,4 +17,5 @@ message ServerInfo_UserAlt {
     optional uint32 depth = 10;       // BFS distance from investigated account; 1 = direct, 2+ = alt-of-alt
     optional uint32 shared_count =
         11; // distinct users sharing the matched identifier; high values suggest VPN/shared network
+    optional uint32 ip_count = 12; // distinct recent session IPs of this account in the search window
 }