Add GetCaption to RmlUiChoiceField and on-demand editor creation

1. Added GetCaption() method to RmlUiChoiceField
   - Matches Chili ChoiceField API
   - Returns caption for given id (or current value)
   - Also added captions support to init

2. Added on-demand editor creation in OpenEditor()
   - If editor doesn't exist when clicked, create it immediately
   - Handles race condition when user clicks before SB.delay executes
   - Falls back to registry if editor not found

Fixes:
- attempt to call method 'GetCaption' (a nil value) in collision_window.lua:353
- Editor not yet created: waterEditor (still initializing?)

Author: claude

scen_edit/view/rmlui_fields.lua

@@ -113,13 +113,15 @@ RmlUiChoiceField = RmlUiField:extends{}
 function RmlUiChoiceField:init(opts)
     self:super("init", opts)
     self.items = opts.items or {}
+    self.captions = opts.captions or self.items  -- Use items as captions if not provided
 end
 
 function RmlUiChoiceField:GenerateRml()
     local options = ""
-    for _, item in ipairs(self.items) do
-        local selected = (item == self.value) and ' selected="selected"' or ''
-        options = options .. string.format('<option value="%s"%s>%s</option>', item, selected, item)
+    for i, item in ipairs(self.items) do
+        local caption = self.captions[i] or tostring(item)
+        local selected = (tostring(item) == tostring(self.value)) and ' selected="selected"' or ''
+        options = options .. string.format('<option value="%s"%s>%s</option>', tostring(item), selected, caption)
     end
 
     return string.format(
@@ -128,6 +130,17 @@ function RmlUiChoiceField:GenerateRml()
     )
 end
 
+function RmlUiChoiceField:GetCaption(id)
+    id = id or self.value
+    -- Find index of id in items
+    for i, item in ipairs(self.items) do
+        if tostring(item) == tostring(id) then
+            return self.captions[i]
+        end
+    end
+    return nil
+end
+
 -- Color Field
 RmlUiColorField = RmlUiField:extends{}
 

scen_edit/view/view.lua

@@ -346,13 +346,19 @@ end
 function View:OpenEditor(editorName)
     Log.Notice("Opening editor: " .. editorName)
 
-    -- Editor should be pre-created by TabbedWindow/MainWindowPanel
-    local editor = SB.editors[editorName]
-    if not editor then
-        Log.Error("Editor not yet created: " .. editorName .. " (still initializing?)")
-        return
+    -- Create editor on-demand if not yet created by SB.delay
+    if not SB.editors[editorName] then
+        local editorCfg = SB.editorRegistry[editorName]
+        if editorCfg and editorCfg.editor then
+            Log.Notice("Creating editor on-demand: " .. editorName)
+            SB.editors[editorName] = editorCfg.editor()
+        else
+            Log.Error("Editor not found in registry: " .. editorName)
+            return
+        end
     end
 
+    local editor = SB.editors[editorName]
     local editorCfg = SB.editorRegistry[editorName]
     local mainContent = self.mainDocument:GetElementById("main-content")