docs: archive the frozen stage code as one compressed tarball

docs/history kept six stages with a full copy of the project under code/,
3.8 mb of sources duplicated from stage to stage and already superseded. store
them as docs/history/code-snapshots.tar.gz, 0.66 mb, and extract one in place
to read it. every stage's notes.md stays browsable, and the index says where the
code went and how to get it back.

the top-level README points at the archive too. its other two links into
docs/history, 21-micro and 35-bench, were notes that were never kept and do not
resolve; the index now records that.

1 files changed, 0 insertions, 19 deletions

diff --git a/docs/history/13-gap-fixes/code/examples/wiring.zc b/docs/history/13-gap-fixes/code/examples/wiring.zc
deleted file mode 100644
index ed30935..0000000
--- a/docs/history/13-gap-fixes/code/examples/wiring.zc
+++ /dev/null
@@ -1,19 +0,0 @@
-// virtual enhancements: custom opcodes wired into the cpu while compiling.
-// the recipes run through the core's optimizer; the jit inlines the result.
-enhance popcount(x) micro
-	"r1 = shr x 1; r1 = and r1 0x55555555; x = sub x r1"
-	"; r1 = shr x 2; r1 = and r1 0x33333333; x = and x 0x33333333; x = add x r1"
-	"; r1 = shr x 4; x = add x r1; x = and x 0x0f0f0f0f; x = mul x 0x01010101; x = shr x 24";
-enhance div10(x) micro "x = udiv x 10";		// becomes a multiply-high, no divide
-enhance hypot2(a, b) vm { 0 $ * ~ 0 $ * + };	// lifted from vm code
-enhance minmax(a, b) -> 2 micro "r2 = min a b; r1 = max a b; r0 = r2";
-let lo, hi;
-fn main()
-{
-	putn(popcount(0xff00ff)); putc(' ');
-	putn(div10(12345)); putc(' ');
-	putn(hypot2(3, 4)); putc(' ');
-	asm { 9 4 minmax hi ! lo ! }
-	putn(lo); putc('/'); putn(hi); putc(10);
-	return 0;
-}