feat(config-settings): value-row set/get backend helpers

functions/__config_settings_get_raw.fish

@@ -0,0 +1,27 @@
+# Copyright (C) 2026 Rootiest
+# SPDX-License-Identifier: AGPL-3.0-or-later
+
+# SYNOPSIS
+#   __config_settings_get_raw <varname>
+#
+# DESCRIPTION
+#   Prints the current value of a universal variable for display in the
+#   config-settings value pages. List variables are printed space-joined.
+#   Prints "DEFAULT" when the variable is unset in every scope.
+#
+# ARGUMENTS
+#   varname  Variable name without the $ prefix
+#
+# RETURNS
+#   0  Always; prints the value or "DEFAULT" to stdout
+#
+# EXAMPLE
+#   set v (__config_settings_get_raw sponge_delay)   # "2" or "DEFAULT"
+function __config_settings_get_raw
+    set -l varname $argv[1]
+    if set -q $varname
+        string join ' ' -- $$varname
+    else
+        echo DEFAULT
+    end
+end

functions/__config_settings_set_value.fish

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+# Copyright (C) 2026 Rootiest
+# SPDX-License-Identifier: AGPL-3.0-or-later
+
+# SYNOPSIS
+#   __config_settings_set_value <varname> <type> <value>
+#
+# DESCRIPTION
+#   Sets a universal config variable from a config-settings value page,
+#   immediately and persistently. An empty <value> erases the variable so the
+#   built-in default takes over. List types split <value> on whitespace; all
+#   other types store it as a single value. When <varname> is a scrollback
+#   variable, the exported SCROLLBACK_HISTORY_* mirror is re-derived so the
+#   POSIX wrappers in the live session see the change without a re-login.
+#
+# ARGUMENTS
+#   varname  Variable name without the $ prefix
+#   type     "list" (whitespace-split) or any other tag (single value)
+#   value    The new value; empty string erases (reset to default)
+#
+# RETURNS
+#   0  Always
+#
+# EXAMPLE
+#   __config_settings_set_value sponge_delay int 5
+#   __config_settings_set_value sponge_successful_exit_codes list "0 1 130"
+#   __config_settings_set_value __fish_scrollback_history_dir path ~/logs
+#   __config_settings_set_value __fish_user_dots_path path ''   # reset
+function __config_settings_set_value
+    set -l varname $argv[1]
+    set -l type    $argv[2]
+    set -l value   $argv[3]
+
+    # stderr suppressed: editing a universal while a global of the same name
+    # shadows it makes interactive fish emit a shadow warning that would
+    # corrupt the in-place panel redraw (see __config_settings_apply).
+    if test -z "$value"
+        set -Ue $varname 2>/dev/null
+    else
+        switch $type
+            case list
+                set -U $varname (string split -n ' ' -- $value) 2>/dev/null
+            case '*'
+                # ponytail: values here are paths/ints/tokens, never leading-dash
+                set -U $varname $value 2>/dev/null
+        end
+    end
+
+    # Scrollback export mirror — POSIX wrappers read these from the env.
+    switch $varname
+        case __fish_scrollback_history_dir
+            if set -q __fish_scrollback_history_dir
+                set -gx SCROLLBACK_HISTORY_DIR $__fish_scrollback_history_dir
+            else
+                set -gx SCROLLBACK_HISTORY_DIR "$HOME/.terminal_history"
+            end
+        case __fish_scrollback_history_max_files
+            if set -q __fish_scrollback_history_max_files
+                set -gx SCROLLBACK_HISTORY_MAX_FILES $__fish_scrollback_history_max_files
+            else
+                set -gx SCROLLBACK_HISTORY_MAX_FILES 100
+            end
+    end
+end