Fix Sta mode: no auto-size window, lazy refresh on sprite change only

- calcPreviewSize ignores Sta mode, uses All sizing (no giant window)
- Refresh timer in Sta only calls refreshSource when sprite version or
  frame changes, not every 0.5s
- Initial refreshSource on entering Sta mode

aniphallow.lua

@@ -1314,15 +1314,14 @@ openPreviewWindow = function()
         S.previewSingleIdx = 1
     end
 
-    -- calcPreviewSize helper
+    -- calcPreviewSize helper (Sta mode excluded — uses last All/One size)
     local function calcPreviewSize()
-        local z = pvZoom()
+        local z
         if S.previewMode == "static" then
-            -- Static mode: show full sprite canvas
-            if app.sprite then
-                return app.sprite.width * z, app.sprite.height * z
-            end
-            return 120, 40
+            -- Don't try to auto-size for Sta; fall through to All sizing
+            z = S.previewZoomAll
+        else
+            z = pvZoom()
         end
         local ptw = S.tileW * z
         local pth = S.tileH * z
@@ -1384,6 +1383,7 @@ openPreviewWindow = function()
                 end
             elseif S.previewMode == "single" then
                 S.previewMode = "static"
+                refreshSource()  -- ensure source image is ready
             else
                 S.previewMode = "all"
             end
@@ -1586,18 +1586,25 @@ openPreviewWindow = function()
     }
     previewTimer:start()
 
+    local pvStaLastVersion = 0  -- track sprite version to detect edits
+    local pvStaLastFrame = 0
+
     pvRefreshTimer = Timer{
         interval = 0.5,
         ontick = function()
-            local prevImg = S.sourceImage
-            refreshSource()
             refreshLockFile()
-            -- In static mode, only repaint if source image changed
             if S.previewMode == "static" then
-                if S.sourceImage ~= prevImg then
+                -- Only refresh source and repaint when sprite actually changed
+                local curVer = app.sprite and app.sprite.version or 0
+                local curFrame = app.frame and app.frame.frameNumber or 0
+                if curVer ~= pvStaLastVersion or curFrame ~= pvStaLastFrame then
+                    pvStaLastVersion = curVer
+                    pvStaLastFrame = curFrame
+                    refreshSource()
                     pcall(function() previewDlg:repaint() end)
                 end
             else
+                refreshSource()
                 pcall(function() previewDlg:repaint() end)
             end