tui: add session rename functionality with /rename command

- Add /rename command to autocomplete when a session is active
- Add rename dialog component for changing session names
- Add rename option to session list dialog with 'r' keybind
- Add session rename command to command registry

packages/opencode/src/cli/cmd/tui/component/dialog-session-rename.tsx

@@ -0,0 +1,35 @@
+import { DialogPrompt } from "@tui/ui/dialog-prompt"
+import { useDialog } from "@tui/ui/dialog"
+import { useSync } from "@tui/context/sync"
+import { createMemo } from "solid-js"
+import { useSDK } from "../context/sdk"
+
+interface DialogSessionRenameProps {
+  session: string
+}
+
+export function DialogSessionRename(props: DialogSessionRenameProps) {
+  const dialog = useDialog()
+  const sync = useSync()
+  const sdk = useSDK()
+  const session = createMemo(() => sync.session.get(props.session))
+
+  return (
+    <DialogPrompt
+      title="Rename Session"
+      value={session()?.title}
+      onConfirm={(value) => {
+        sdk.client.session.update({
+          path: {
+            id: props.session,
+          },
+          body: {
+            title: value,
+          },
+        })
+        dialog.clear()
+      }}
+      onCancel={() => dialog.clear()}
+    />
+  )
+}