Esc alternates between the last two panes; Toggleterm is gone

Esc ran Toggleterm, which hopped between the newest DOC and the newest
TERMINAL. That distinction never earned its keep. It made Esc unpredictable —
which of three panes you landed on depended on their kinds, not on where you
had been — and it could not alternate between two files at all, which is the
case you hit most. Editing two files, Esc did nothing.

The replacement already existed. Last (SPC j j) is "the pane you were in
before this one, whichever it was": it walks the jump stack for the newest
entry naming a different pane and restores its line and column. So Esc, and
Shift-Esc in tty, now run Last, and Toggleterm is deleted rather than renamed
— a third implementation of "go to the other pane" was the thing to avoid.
SPC w t goes with it; the w group is the four directional moves, and the jump
group already had SPC j j.

Held down, Esc alternates. Two files, a file and its shell, a file and a
+Search — all the same, because Last has no notion of kind to get wrong.

This depends on the swap in the same series: Last reads the stack backwards,
and until hopping stopped appending, the pane you came from could fall off it.

windownav.snap needed only its keys and prose changed — its golden did not
move at all, which is the useful evidence here: for the one scenario the old
builtin handled well, Last produces an identical focus sequence.

Coverage for what it did not handle is new: a unit test opens a second FILE by
looking its name and asserts Esc alternates between two panes of the SAME
kind, which is the case that used to be a no-op.

Docs follow: tutor.txt, docs/helix-keys.md, docs/design.typ, and the builtin
index goldens, which are now one row shorter.

75/75 snapshots, both unit suites, and the macOS ABI build all pass.

1 files changed, 13 insertions, 13 deletions

diff --git a/test/snapshots/selregex.golden b/test/snapshots/selregex.golden
index 8317a2a6..59dc5d86 100644
--- a/test/snapshots/selregex.golden
+++ b/test/snapshots/selregex.golden
@@ -1,6 +1,6 @@
 == snap prompt-armed grid=160x24 cursor=11,23
 |New Newcol Find Grep Help Tutor Dump NextColor Debug Kill
-|  /tmp/pardes-snap/selregex/cwd/m.zig Save New Del
+|  /tmp/pardes-snap/selregex/cwd/m.zig                                                                                           Save New Del
 |     1 const one = 1;
 |     2 const two = 2;
 |     3 const three = 3;
@@ -25,7 +25,7 @@
 |   Select /
 == snap preview grid=160x24 cursor=16,23
 |New Newcol Find Grep Help Tutor Dump NextColor Debug Kill
-|  /tmp/pardes-snap/selregex/cwd/m.zig Save New Del
+|  /tmp/pardes-snap/selregex/cwd/m.zig                                                                                           Save New Del
 |     1 const one = 1;
 |     2 const two = 2;
 |     3 const three = 3;
@@ -50,7 +50,7 @@
 |   Select /const
 == style preview
 |0: 0-56 #949494,#121212, 57-159 d,#121212,
-|1: 0-1 #ffffff,#626262, 2-49 #949494,#121212, 50-159 d,#121212,
+|1: 0-1 #ffffff,#626262, 2-139 #949494,#121212, 140-159 d,#121212,
 |2: 0-0 d,#444444, 1-1 d,#080808, 2-6 #626262,#080808, 7-10 #080808,#80a0ff, 11-11 #80a0ff,#080808, 12-18 #bdbdbd,#080808, 19-19 #e3c78a,#080808, 20-20 #bdbdbd,#080808, 21-159 d,#080808,
 |3: 0-0 d,#444444, 1-1 d,#080808, 2-6 #626262,#080808, 7-10 #080808,#445483, 11-11 #80a0ff,#080808, 12-18 #bdbdbd,#080808, 19-19 #e3c78a,#080808, 20-20 #bdbdbd,#080808, 21-159 d,#080808,
 |4: 0-0 d,#444444, 1-1 d,#080808, 2-6 #626262,#080808, 7-10 #080808,#445483, 11-11 #80a0ff,#080808, 12-20 #bdbdbd,#080808, 21-21 #e3c78a,#080808, 22-22 #bdbdbd,#080808, 23-159 d,#080808,
@@ -72,10 +72,10 @@
 |20: 0-0 d,#444444, 1-1 d,#080808, 2-6 #626262,#080808, 7-159 d,#080808,
 |21: 0-0 d,#444444, 1-1 d,#080808, 2-6 #626262,#080808, 7-159 d,#080808,
 |22: 0-0 d,#444444, 1-1 d,#080808, 2-6 #626262,#080808, 7-159 d,#080808,
-|23: 0-0 d,#444444, 1-1 d,#080808, 2-15 #949494,#121212, 16-159 d,#121212,
+|23: 0-0 d,#444444, 1-1 d,#080808, 2-15 #bdbdbd,#080808, 16-159 d,#080808,
 == snap three-selected grid=160x24 cursor=11,2
 |New Newcol Find Grep Help Tutor Dump NextColor Debug Kill
-|  /tmp/pardes-snap/selregex/cwd/m.zig Save New Del
+|  /tmp/pardes-snap/selregex/cwd/m.zig                                                                                           Save New Del
 |     1 const one = 1;
 |     2 const two = 2;
 |     3 const three = 3;
@@ -100,7 +100,7 @@
 |
 == style three-selected
 |0: 0-56 #949494,#121212, 57-159 d,#121212,
-|1: 0-1 #ffffff,#626262, 2-49 #949494,#121212, 50-159 d,#121212,
+|1: 0-1 #ffffff,#626262, 2-139 #949494,#121212, 140-159 d,#121212,
 |2: 0-0 d,#444444, 1-1 d,#080808, 2-6 #949494,#121212, 7-11 #080808,#80a0ff, 12-18 #bdbdbd,#080808, 19-19 #e3c78a,#080808, 20-20 #bdbdbd,#080808, 21-159 d,#080808,
 |3: 0-0 d,#444444, 1-1 d,#080808, 2-6 #626262,#080808, 7-10 #080808,#445483, 11-11 #80a0ff,#080808, 12-18 #bdbdbd,#080808, 19-19 #e3c78a,#080808, 20-20 #bdbdbd,#080808, 21-159 d,#080808,
 |4: 0-0 d,#444444, 1-1 d,#080808, 2-6 #626262,#080808, 7-10 #080808,#445483, 11-11 #80a0ff,#080808, 12-20 #bdbdbd,#080808, 21-21 #e3c78a,#080808, 22-22 #bdbdbd,#080808, 23-159 d,#080808,
@@ -125,7 +125,7 @@
 |23: 0-0 d,#444444, 1-1 d,#080808, 2-6 #626262,#080808, 7-159 d,#080808,
 == snap narrowed grid=160x24 cursor=12,23
 |New Newcol Find Grep Help Tutor Dump NextColor Debug Kill
-|  /tmp/pardes-snap/selregex/cwd/m.zig Save New Del
+|  /tmp/pardes-snap/selregex/cwd/m.zig                                                                                           Save New Del
 |     1 const one = 1;
 |     2 const two = 2;
 |     3 const three = 3;
@@ -150,7 +150,7 @@
 |   Select /t
 == style narrowed
 |0: 0-56 #949494,#121212, 57-159 d,#121212,
-|1: 0-1 #ffffff,#626262, 2-49 #949494,#121212, 50-159 d,#121212,
+|1: 0-1 #ffffff,#626262, 2-139 #949494,#121212, 140-159 d,#121212,
 |2: 0-0 d,#444444, 1-1 d,#080808, 2-6 #626262,#080808, 7-10 #bdbdbd,#080808, 11-11 #80a0ff,#080808, 12-18 #bdbdbd,#080808, 19-19 #e3c78a,#080808, 20-20 #bdbdbd,#080808, 21-159 d,#080808,
 |3: 0-0 d,#444444, 1-1 d,#080808, 2-6 #626262,#080808, 7-10 #bdbdbd,#080808, 11-11 #80a0ff,#080808, 12-18 #bdbdbd,#080808, 19-19 #e3c78a,#080808, 20-20 #bdbdbd,#080808, 21-159 d,#080808,
 |4: 0-0 d,#444444, 1-1 d,#080808, 2-6 #626262,#080808, 7-10 #bdbdbd,#080808, 11-11 #80a0ff,#080808, 12-20 #bdbdbd,#080808, 21-21 #e3c78a,#080808, 22-22 #bdbdbd,#080808, 23-159 d,#080808,
@@ -172,10 +172,10 @@
 |20: 0-0 d,#444444, 1-1 d,#080808, 2-6 #626262,#080808, 7-159 d,#080808,
 |21: 0-0 d,#444444, 1-1 d,#080808, 2-6 #626262,#080808, 7-159 d,#080808,
 |22: 0-0 d,#444444, 1-1 d,#080808, 2-6 #626262,#080808, 7-159 d,#080808,
-|23: 0-0 d,#444444, 1-1 d,#080808, 2-11 #949494,#121212, 12-159 d,#121212,
+|23: 0-0 d,#444444, 1-1 d,#080808, 2-11 #bdbdbd,#080808, 12-159 d,#080808,
 == snap esc-restores grid=160x24 cursor=11,2
 |New Newcol Find Grep Help Tutor Dump NextColor Debug Kill
-|  /tmp/pardes-snap/selregex/cwd/m.zig Save New Del
+|  /tmp/pardes-snap/selregex/cwd/m.zig                                                                                           Save New Del
 |     1 const one = 1;
 |     2 const two = 2;
 |     3 const three = 3;
@@ -200,7 +200,7 @@
 |
 == style esc-restores
 |0: 0-56 #949494,#121212, 57-159 d,#121212,
-|1: 0-1 #ffffff,#626262, 2-49 #949494,#121212, 50-159 d,#121212,
+|1: 0-1 #ffffff,#626262, 2-139 #949494,#121212, 140-159 d,#121212,
 |2: 0-0 d,#444444, 1-1 d,#080808, 2-6 #949494,#121212, 7-11 #080808,#80a0ff, 12-18 #bdbdbd,#080808, 19-19 #e3c78a,#080808, 20-20 #bdbdbd,#080808, 21-159 d,#080808,
 |3: 0-0 d,#444444, 1-1 d,#080808, 2-6 #626262,#080808, 7-10 #080808,#445483, 11-11 #80a0ff,#080808, 12-18 #bdbdbd,#080808, 19-19 #e3c78a,#080808, 20-20 #bdbdbd,#080808, 21-159 d,#080808,
 |4: 0-0 d,#444444, 1-1 d,#080808, 2-6 #626262,#080808, 7-10 #080808,#445483, 11-11 #80a0ff,#080808, 12-20 #bdbdbd,#080808, 21-21 #e3c78a,#080808, 22-22 #bdbdbd,#080808, 23-159 d,#080808,
@@ -225,7 +225,7 @@
 |23: 0-0 d,#444444, 1-1 d,#080808, 2-6 #626262,#080808, 7-159 d,#080808,
 == snap commented grid=160x24 cursor=14,2
 |New Newcol Find Grep Help Tutor Dump NextColor Debug Kill
-|  /tmp/pardes-snap/selregex/cwd/m.zig Save New Del
+|  /tmp/pardes-snap/selregex/cwd/m.zig                                                                                           Save New Del
 |     1 // const one = 1;
 |     2 // const two = 2;
 |     3 // const three = 3;
@@ -250,7 +250,7 @@
 |
 == snap uncommented grid=160x24 cursor=11,2
 |New Newcol Find Grep Help Tutor Dump NextColor Debug Kill
-|  /tmp/pardes-snap/selregex/cwd/m.zig Save New Del
+|  /tmp/pardes-snap/selregex/cwd/m.zig                                                                                           Save New Del
 |     1 const one = 1;
 |     2 const two = 2;
 |     3 const three = 3;