fix(mdviewer): restore innerHTML update in file:rendered and reset syncId on file switch

The doc-cache refactoring removed content.innerHTML = parseResult.html
from the file:rendered handler, breaking CM→iframe content sync.
Also reset _lastReceivedSyncId and _syncId on file switch/set content
to prevent stale syncId rejection after MarkdownSync reactivation.

Author: abose

src-mdviewer/src/bridge.js

@@ -321,6 +321,9 @@ export function initBridge() {
 function handleSetContent(data) {
     const { markdown, baseURL, filePath } = data;
 
+    // Reset sync tracking — Phoenix resets its counter on activate
+    _lastReceivedSyncId = -1;
+
     if (baseURL) {
         _baseURL = baseURL;
     }
@@ -398,6 +401,10 @@ function handleUpdateContent(data) {
 function handleSwitchFile(data) {
     const { filePath, markdown, baseURL } = data;
 
+    // Reset sync tracking — Phoenix resets its counter on activate
+    _lastReceivedSyncId = -1;
+    _syncId = 0;
+
     if (baseURL) {
         _baseURL = baseURL;
     }

src-mdviewer/src/components/viewer.js

@@ -56,6 +56,9 @@ export function initViewer() {
         const content = getContentEl();
         if (!content) return;
 
+        content.innerHTML = parseResult.html;
+        content.dir = "auto";
+
         wrapTables();
         await renderAfterHTML(content, parseResult);