feat(workspace): split menus start AI tools; drop the Tools menu

A pane's split right/down menus offered only New terminal. They now list
the same AI tools as the tab bar's + menu (newTabTools/newTabBody,
shared from ConsoleTabs), started bare in the first free slot on that
side of the pane.

The tab bar's Tools menu is gone: its readme run hit 409 ERUNLIVE
whenever slot 0 was live (always, in the session view) and depended on
a personal skill; MCP sync and the dev-sync check served the dormant
ship-feature-lane pipeline. The sidebar row menu's readme item goes too.
The routes stay, reached by `agenthub lanes mcp sync` and
`agenthub lanes sync-base`.

Also: the home's Memory header and file tabs no longer shrink (a long
file squeezed the tab row and clipped it).

client/src/components/lanes/WorkspaceRowMenu.tsx

@@ -2,8 +2,7 @@
  * @file WorkspaceRowMenu — the sidebar workspace row's context menu, opened at
  * the pointer (right-click) or under the row's `⋯` button. Every item is an
  * existing call: Start/Stop (`POST /api/lanes/:id/start` slot 0 / `stop`),
- * Rename (the row's inline field), Create/update readme (claude only, the same run
- * the lane Tools menu starts), New workspace here (the Add modal prefilled),
+ * Rename (the row's inline field), New workspace here (the Add modal prefilled),
  * Copy path, and Reset/Remove through `DestructiveLaneModal` — Reset only on a
  * managed lane. The server's guards are the real ones; the menu only hides
  * what the lane's kind or tool makes meaningless. The shell (position,
@@ -59,23 +58,6 @@ export function WorkspaceRowMenu({
         {live ? t("menu.stop") : t("menu.start")}
       </MenuItem>
       <MenuItem onSelect={() => onAction("rename")}>{t("menu.rename")}</MenuItem>
-      {lane.tool === "claude" && (
-        <MenuItem
-          onSelect={() =>
-            void run(
-              () =>
-                api.run.start({
-                  laneId: lane.id,
-                  cwd: lane.cwd,
-                  initialPrompt: "/sg-all:sg-md-writing",
-                }),
-              "started"
-            )
-          }
-        >
-          {t("actions.writeDocs")}
-        </MenuItem>
-      )}
       <MenuItem onSelect={() => onAction("new-here")}>{t("menu.newHere")}</MenuItem>
       <MenuItem onSelect={() => void run(() => navigator.clipboard.writeText(lane.cwd))}>
         {t("menu.copyPath")}