require display_as to be a lower case word in .entry.json

The `display_as` field in an `.entry_json` file must match
the regex `^[a-z][0-9a-z]*$` now.  This is needed to reduce
errors during the final round while converting a potential
submission to entry form.

Modify `1992/buzzard.2/.entry.json` and
`1993/rince/.entry.json` to change `display_as` field
to use lower case.

Correct `2012/omoikane/.entry.json` to correctly
reflect changes made by commit 2955e5d07e
and commit 2955e5d07e.

Change `bin/cvt-submission.sh` to verify that the `display_as`
matches the above regex.

Changed `bin/cvt-submission.sh` VERSION from "2.2.2 2025-06-30"
to "2.3.0 2025-07-02".

Rebuild all tarballs, both at the entry and the year level
due recent changes to `var.mk`, `1337.mk`, and `ioccc.css`.

Rebuild sitemap due to the changes above.

Ran `make update` to test and perform the above.

2012/omoikane/.entry.json

@@ -21,14 +21,6 @@
             "display_via_github" : true,
             "entry_text" : "entry Makefile"
         },
-        {
-            "file_path" : "binmode_main.h",
-            "inventory_order" : 200,
-            "OK_to_edit" : true,
-            "display_as" : "c",
-            "display_via_github" : true,
-            "entry_text" : "Preprocessor hack to set binary mode"
-        },
         {
             "file_path" : "omoikane.alt.c",
             "inventory_order" : 40,
@@ -37,6 +29,14 @@
             "display_via_github" : true,
             "entry_text" : "alternate source code"
         },
+        {
+            "file_path" : "binmode_main.h",
+            "inventory_order" : 40,
+            "OK_to_edit" : true,
+            "display_as" : "c",
+            "display_via_github" : true,
+            "entry_text" : "preprocessor hack to set binary mode"
+        },
         {
             "file_path" : "omoikane.orig.c",
             "inventory_order" : 50,