sl0ppty: bindings that need no leader

Every binding needed the prefix first, which is the safe design and the
reason a leader exists: a multiplexer that takes chords away from the
programs inside it is a multiplexer you fight. But it is the user's keyboard.
Somebody who wants ctrl+alt+arrow to move between panes should be allowed to
have it, including the part where that chord stops reaching vim.

    keys {
        direct {
            bind "ctrl+alt+left" "focus-left"
            bind "ctrl+alt+right" "focus-right"
        }
    }

A block rather than a flag on each line, because these take a chord away from
every program in every pane, and that is worth seeing at a glance -- and
worth having somewhere to write the warning down, which the config now does
in full: prefer chords no program wants, a bare letter certainly is not one,
`none` gives it back.

Three ordering decisions hold it together, none of them obvious from reading
the code, all three tested:

- the direct lookup happens *last* in the key path -- after the rename editor,
  the finder, the cheatsheet, and the prefix itself. An overlay still owns the
  keyboard, and a direct binding cannot shadow the leader, which would make
  the leader unusable with no way back. There is a test that tries exactly
  that and finds the prefix still working.
- `direct` is part of a binding's identity rather than a property of it. `x`
  after the leader and `x` on its own are two bindings; binding one must not
  silently redefine the other.
- the after-the-leader lookup falls through to direct bindings, so pressing
  the prefix first never makes a binding stop working. A rule you have to
  keep track of is a rule that will catch you out.

The cheatsheet lists them under "without the leader", apart from the rest,
because the caption at the top of it says "<prefix> then:" and these are
precisely the ones that is not true of.

The tests state the bargain rather than just the mechanism: the chord fires
with no leader, and what it fires on, the program never sees -- asserted with
`cat -v`, so a keystroke arriving in the pane is visible on screen rather
than an invisible control byte that would prove nothing either way.

1 files changed, 21 insertions, 0 deletions

diff --git a/config/config.kdl b/config/config.kdl
index 5e26c8e..c67519b 100644
--- a/config/config.kdl
+++ b/config/config.kdl
@@ -494,4 +494,25 @@ keys {
     bind "end" "scroll-bottom"
     bind "d" "detach"
     bind "q" "quit"
+
+    // ── bindings that need no leader ────────────────────────────────────────
+    //
+    // Anything in here fires the moment you press it, with no prefix first.
+    // That also means the chord is *gone* from every program in every pane:
+    // vim will never see it, your shell will never see it, and the only sign
+    // will be that the key does not work in there any more.
+    //
+    // It is a footgun and it is yours: this is your keyboard, and a
+    // multiplexer that refuses to get out of the way is its own kind of
+    // wrong. Prefer chords no program wants -- ctrl+alt+something is usually
+    // safe, a bare letter certainly is not.
+    //
+    // `none` gives a chord back, the same as anywhere else.
+    //
+    // direct {
+    //     bind "ctrl+alt+left" "focus-left"
+    //     bind "ctrl+alt+right" "focus-right"
+    //     bind "ctrl+alt+up" "focus-up"
+    //     bind "ctrl+alt+down" "focus-down"
+    // }
 }