Delete extra themes from the theme picker (#14713)

* Delete extra themes from the theme picker

Delete on an extra (user-installed) theme opens the shared faded confirmation dialog; confirming runs omarchy-theme-remove and selection lands on the theme before the deleted one. Stock themes and user overrides of them are not offered for deletion, apply/re-ask are blocked while a removal runs, and row refreshes queue so a deletion never leaves the list stale.

* Fail closed on theme deletion until stock themes are known

Keep Delete disabled until the stock listing finishes successfully, so a stock override cannot look deletable in the startup window. Also hold theme apply (and further delete asks) from removal exit until the refreshed rows load, so Enter cannot apply the just-deleted theme in the gap.

shell/plugins/image-picker/ImagePickerModel.js

@@ -6,6 +6,41 @@ function labelForPath(path) {
   return nameForPath(path).replace(/[-_]+/g, " ").replace(/\b\w/g, function(match) { return match.toUpperCase() })
 }
 
+// Extra (user-installed) theme names, one per line, as listed from the user
+// themes directory: the set omarchy-theme-remove can delete.
+function parseThemeNames(text) {
+  var names = []
+  var lines = String(text || "").split("\n")
+  for (var i = 0; i < lines.length; i++) {
+    var name = lines[i].trim()
+    if (name) names.push(name)
+  }
+  return names
+}
+
+// A user directory shadowing a stock theme holds customizations, not an
+// extra theme: removing it from here would silently revert to stock (and a
+// shadow can even list twice, once per preview extension), so only themes
+// with no stock twin can be deleted from the picker.
+function canDeleteTheme(name, extraNames, stockNames) {
+  if (!name || !Array.isArray(extraNames) || extraNames.indexOf(name) === -1) return false
+  return !Array.isArray(stockNames) || stockNames.indexOf(name) === -1
+}
+
+// Where selection lands when the selected image goes away: the previous
+// match in list order, or the next one when the first match is deleted.
+function replacementSelectionPath(images, selectedIndex, filterText) {
+  var values = Array.isArray(images) ? images : []
+  if (selectedIndex < 0 || selectedIndex >= values.length) return ""
+  for (var i = selectedIndex - 1; i >= 0; i--) {
+    if (itemMatches(values, i, filterText)) return values[i].filePath
+  }
+  for (var i = selectedIndex + 1; i < values.length; i++) {
+    if (itemMatches(values, i, filterText)) return values[i].filePath
+  }
+  return ""
+}
+
 function loadRows(rows) {
   var images = []
   var seen = {}
@@ -125,6 +160,9 @@ if (typeof module !== "undefined") {
   module.exports = {
     nameForPath: nameForPath,
     labelForPath: labelForPath,
+    parseThemeNames: parseThemeNames,
+    canDeleteTheme: canDeleteTheme,
+    replacementSelectionPath: replacementSelectionPath,
     loadRows: loadRows,
     itemMatches: itemMatches,
     firstMatchingIndex: firstMatchingIndex,