fix(mcp-server): review fixes for the shell's sync core

A recovery loads the server's diagram in full and waits for draw.io's
load report, as the classic page does: whether the canvas takes a write
in place is decided inside DiagramProvider, and an autosave of the
canvas being replaced went to the server as an edit when the decision
was wrong. A paper size change alone is pushed again: autosaves are
compared as documents only for draw.io's own copy of a committed write.
A projection stays on screen until draw.io reports the restore load
(5 s at most), the whole export ends in 15 s even when its result POST
hangs, and an export in flight is dropped when draw.io starts over. A
refused poll shows the tab offline. With several pages and the page on
screen unknown, a write loads in full. hasLoadOnlySettings and the
highlight of an AI change are shared with the editor bridge.

components/chat/use-versions.ts

@@ -4,7 +4,10 @@ import { toast } from "sonner"
 import { useDiagram } from "@/contexts/diagram-context"
 import { useDictionary } from "@/hooks/use-dictionary"
 import { diffDiagrams, isSameDocument } from "@/lib/diagram-diff"
-import { clearHighlights, highlightCells } from "@/lib/drawio/editor-bridge"
+import {
+    clearHighlights,
+    highlightChangedCells,
+} from "@/lib/drawio/editor-bridge"
 import { formatMessage } from "@/lib/i18n/utils"
 import { BLANK_MXFILE } from "@/packages/mcp-server/src/pages.ts"
 import { useVersionsStore } from "@/stores/versions-store"
@@ -63,14 +66,7 @@ export function useVersions({
                 fromScratch,
             })
             // Mark what changed, unless the whole diagram is new
-            if (!fromScratch) {
-                setTimeout(() => {
-                    const marker = getComputedStyle(document.documentElement)
-                        .getPropertyValue("--marker")
-                        .trim()
-                    highlightCells(touchedIds, marker || "#ffd84d")
-                }, 60)
-            }
+            if (!fromScratch) highlightChangedCells(touchedIds)
             // The picture is of the canvas: take it right away, before a
             // newer version can be on it; once one is, this one gets none
             // rather than the newer one's