Map Place, Open, Image Size in percent, the Paint Bucket and Insert Conditional (#219) (#4470)

- image.imageSize takes percent (both sides; an explicit side wins).
- actions.conditional {if, then, else}: Photoshop's Insert Conditional as a step, 33 conditions
  on the document (shape, mode, depth, selection, layers, alpha channels, unsaved) and the
  active layer (kind, locks, visibility, masks, effects); a failing branch stops the caller.
- .atn events: placeEvent → file.placeEmbedded/placeLinked (path, scale), open → file.openAs,
  imageSize in percent, fill from a point → paint.bucket (pixels), conditional. 105 → 108.
- Panel labels conditional steps as 'If cond → then / else'.

docs/control-protocol.md

@@ -535,7 +535,10 @@ step with its dialog on opens that command's dialog seeded with the recorded val
 the play result carries `paused: {step, id, dialog}`, OK runs the dialog's values and continues
 from the next step, Cancel stops the action. Agents (`automation_input`) play headlessly with the
 recorded values. The panel menu's **Insert Stop…** adds an `actions.stopMessage` step after the
-selected step (`actions.insert` takes any command id and params).
+selected step (`actions.insert` takes any command id and params). `actions.conditional {if, then,
+else}` is Photoshop's Insert Conditional as a step: it tests the document or active layer
+(`always`, `landscape`, `modeIsRGB`, `hasLayers`, `isBackground`, `hasPixelMask`… see its params)
+and plays the matching action by name, failing the caller when that action fails.
 
 Layer-panel **Quick Export as PNG** exports every selected layer as a separate PNG. A single
 Save dialog chooses the first filename; remaining files are numbered siblings with sanitized