Edit workspace files directly on web (#2270)

* feat(files): edit workspace files on web

Keep source buffers synchronized with host file changes and require an explicit overwrite or reload when revisions diverge.

* feat(panels): surface and protect modified tabs

Expose tooltip and modification state through the generic panel boundary so tabs can show stable metadata and guard every close route consistently.

* fix(tests): use portable fake timeout handle

* fix(files): harden editor conflict handling

Preserve modified panel state across tab eviction, use precise revisions for optimistic writes, coalesce concurrent file watchers, and localize the editor interface.

* fix(files): close editor concurrency gaps

Coalesce clean reloads, preserve subscriber identities and file permissions, suspend pending saves during close confirmation, and carry precise revisions through file reads.

* test(files): expect read revision metadata

packages/app/src/components/split-container.tsx

@@ -55,6 +55,7 @@ import {
   getWorkspacePaneDescriptors,
 } from "@/screens/workspace/workspace-pane-state";
 import { useMountedTabSet } from "@/screens/workspace/use-mounted-tab-set";
+import { useModifiedPanelTabIds } from "@/panels/panel-instance-attributes";
 import {
   WorkspacePaneContent,
   type WorkspacePaneContentModel,
@@ -934,11 +935,17 @@ function SplitPaneView({
   );
   const paneTabs = useMemo(() => paneState.tabs.map((tab) => tab.descriptor), [paneState.tabs]);
   const paneTabIds = useMemo(() => paneTabs.map((tab) => tab.tabId), [paneTabs]);
+  const modifiedPaneTabIds = useModifiedPanelTabIds({
+    serverId: normalizedServerId,
+    workspaceId: normalizedWorkspaceId,
+    tabIds: paneTabIds,
+  });
   const tabDescriptorMap = useStableTabDescriptorMap(paneTabs);
   const activeTabDescriptor = paneState.activeTab?.descriptor ?? null;
   const { mountedTabIds } = useMountedTabSet({
     activeTabId: activeTabDescriptor?.tabId ?? null,
     allTabIds: paneTabIds,
+    retainedTabIds: modifiedPaneTabIds,
     cap: 3,
   });
   const mountedPaneTabIds = useMemo(