feat(config): add down-arrow binding for silent pj invocation on empty prompt

dot_config/fish/functions/_pj_bind_down.fish

@@ -0,0 +1,18 @@
+function _pj_bind_down --description "down arrow: pj on an idle empty prompt, else the preset down-or-search"
+    # Mirror of atuin's up binding (atuin owns up, this owns down). Everything
+    # that legitimately needs the arrow keys keeps them:
+    #   - non-empty buffer  → multiline cursor movement / forward history search
+    #   - paging mode       → tab-completion pager navigation (tab on an empty
+    #                         line opens the pager with an empty buffer)
+    #   - search mode       → history-search navigation
+    set -l buf (commandline | string collect)
+    if test -n "$buf"; or commandline --paging-mode; or commandline --search-mode
+        commandline -f down-or-search
+        return
+    end
+
+    # PJ_QUIET keeps pj silent when the tree has no package.json, so down is a
+    # no-op outside JS projects instead of printing an error on every press.
+    PJ_QUIET=1 pj
+    commandline -f repaint
+end

dot_config/fish/functions/fish_user_key_bindings.fish

@@ -19,6 +19,11 @@ function fish_user_key_bindings
         bind -M $mode ctrl-p 'pj; commandline -f repaint'
         bind -M $mode ctrl-a 'omp; commandline -f repaint'
 
+        # Arrow keys: atuin owns up (bound from config.fish, survives the
+        # fish_vi_key_bindings reset above because that only erases presets),
+        # down runs pj — but only on an idle, empty prompt; see _pj_bind_down.
+        bind -M $mode down _pj_bind_down
+
         # ctrl-f: pick file(s) with television and open in nvim.
         bind -M $mode ctrl-f 'yy; commandline -f repaint'
         bind -M $mode ctrl-g 'lazygit; commandline -f repaint'

dot_config/fish/functions/pj.fish

@@ -12,7 +12,9 @@ function pj --description "fzf package.json script runner with auto-detected pac
     end
 
     if test -z "$pkg"
-        echo "pj: no package.json found in this tree" >&2
+        # PJ_QUIET: called from the down-arrow binding, where a missing
+        # package.json is the normal case and must not print anything.
+        test -n "$PJ_QUIET"; or echo "pj: no package.json found in this tree" >&2
         return 1
     end
     set -l root (path dirname $pkg)