update IOCCC28 open and judging dates

The IOCCC28 will now open on **2025-03-05 23:19:17.131107 UTC**
and enter the judging state on **2025-06-05 04:03:02.010099 UTC**.

Updated sitemap, added news for 2025-02-12, and updated the status.

Performed `make www gen_status gen_sitemap timestamp` on macOS to complete the above.

status.html

@@ -435,7 +435,7 @@
         "no_comment" : "mandatory comment: because comments were removed from the original JSON spec",
         "IOCCC_status_version" : "1.0 2024-03-09",
         "contest_status" : "pending",
-        "news_update" : "2025-01-30T22:17:38+00:00",
+        "news_update" : "2025-02-13T00:39:06+00:00",
         "status_update" : "2024-12-29T10:01:35+00:00"
     }</code></pre>