Stop committing assembled programs, nine of which had gone stale

Thirteen build artifacts were tracked: ten .bin files, a disk image, and the
text file that had been put on it. Every one is produced by 'make' in
Programs/ from a source file that is also tracked.

NINE OF THE TEN BINARIES DISAGREED WITH THEIR OWN SOURCE, including
Programs/CosmOS/Bin/cosmos.bin - the operating system. Only hello.bin still
matched, and that by accident.

That is worse than shipping no binary at all. A repository holding both a
source file and a stale build of it has two answers to what a program does,
and the wrong one is the one that runs. Somebody reads the source, runs the
binary, and sees behaviour that is not in the code with nothing to tell them
why.

Nothing referenced any of them - not the makefiles, not the tests, not the
manuals. Checked before removing, and checked after: the suite passes, and a
clean clone with all of them gone builds both tools and assembles every
program from source alone.

.gitignore now covers *.bin, *.sbx and *.img, unanchored, because a build
output may appear anywhere a source file lives.

Programs/CosmOS/Bin/ held cosmos.bin, disk.img and a 17 byte hello.txt that
existed only to be put on that image. It was a snapshot of a demo from
before Tests/makedisks.sh built its own fixtures, and it goes with them.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01E2JrLzFvuFX9fgi1LDRjrW

.gitignore

@@ -13,3 +13,13 @@
 
 # Python leaves these beside the test scripts.
 __pycache__/
+
+# Assembled programs. Every one of these is built by 'make' in Programs/ from a source
+# file that is tracked, so committing them only creates a second answer to the question of
+# what a program does - and the second answer goes stale silently. Nine of the ten that
+# used to be here disagreed with their own source, including the operating system.
+#
+# Not anchored, because a .bin may be built anywhere a .asm lives.
+*.bin
+*.sbx
+*.img