Bump libakgl to pick up the six defects this port filed

Records the filing in TODO.md section 7 alongside the FILTER gap, and names the
four workarounds this repository carries against them -- the embedded-dependency
CMake trick, the akgl/actor.h include ahead of akgl/controller.h, and the
hand-populated render vtable with its NULL-deref hazard. Each is commented at its
site with the words "filed upstream" so it can be found and deleted when the
fixes land.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

TODO.md

@@ -750,7 +750,15 @@ Building against any of it needs `-DAKBASIC_WITH_AKGL=ON`, which pulls in `libak
 submodules (SDL and friends). Those are not initialized in a default clone; `git submodule
 update --init --recursive` gets them.
 
-**One gap is outstanding, and upstream named it itself.** The commit that added the audio API
+**Six items are filed upstream and outstanding**, at `deps/libakgl/TODO.md` items 5-9 of "API
+gaps blocking akbasic" and item 14 of "Defects". Four are workarounds this repository carries
+today, each commented at its site with the words "filed upstream" so it can be found and
+deleted: the embedded-dependency CMake trick in our `CMakeLists.txt`, the `akgl/actor.h`
+include in `src/input_akgl.c`, and the hand-populated vtable and its NULL-deref hazard in
+`tests/akgl_backends.c`. §3 describes all four. The fifth is `SOUND`'s frequency sweep and the
+sixth is the missing version bump recorded in §8.
+
+**One further gap is outstanding, and upstream named it itself.** The commit that added the audio API
 says plainly what it does not cover: *"Still missing for a complete BASIC sound vocabulary:
 `FILTER` (SDL3 has no filter primitive; this would need writing), `TEMPO` and the `PLAY`
 note-string parser, both of which belong in the interpreter rather than here."*