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3.8 mb of sources duplicated from stage to stage and already superseded.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, 24 deletions

diff --git a/docs/history/15-o3/code/tests/arrays.zc b/docs/history/15-o3/code/tests/arrays.zc
deleted file mode 100644
index f8d46d8..0000000
--- a/docs/history/15-o3/code/tests/arrays.zc
+++ /dev/null
@@ -1,24 +0,0 @@
-// growable arrays and fixed ones
-struct point { int x, y; };
-fn main()
-{
-	let before = live_objects();
-	{
-		[]int a = new([]int);
-		for (int i = 0; i < 100; i++) push(a, i * i);
-		putn(len(a)); putc(' '); putn(cap(a)); putc(' '); putn(a[99]); putc(' ');
-		putn(pop(a)); putc(' '); putn(len(a)); putc(' ');
-		resize(a, 3); putn(len(a)); putc(' '); putn(a[2]); putc(' ');
-		fixed []int f = new(fixed []int, 5);
-		f[4] = 7; putn(f[4] + len(f)); putc(' ');
-		[]point ps = new([]point, 2);
-		ps[1].y = 9; resize(ps, 10); putn(ps[1].y + len(ps)); putc(' ');
-		[8]int st; putn(len(st)); putc(' ');
-		[]*point owned = new([]*point);
-		for (int i = 0; i < 20; i++) { *point p = new(point); p.x = i; push(owned, d*p); }
-		putn(owned[19].x); putc(' ');
-		putn(live_objects() - before); putc(10);
-	}
-	putn(live_objects() - before); putc(10);
-	return 0;
-}