fix(pi-ssh): harden remote execution and search

pi-ssh/src/remote-bash.ts

@@ -0,0 +1,27 @@
+import type { BashOperations } from "@earendil-works/pi-coding-agent";
+import type { RemoteTransport } from "./ssh2-transport.ts";
+
+export interface RemoteBashConnection {
+  remoteCwd: string;
+}
+
+/**
+ * Adapt Pi's Bash output machinery to the active remote workspace.
+ *
+ * The cwd supplied by Pi's Bash factory is deliberately ignored: it belongs
+ * to the factory's filesystem namespace and must never leak into SSH command
+ * execution. The connection's mutable remoteCwd is the sole shell base.
+ */
+export function createRemoteBashOps(
+  connection: RemoteBashConnection,
+  transport: RemoteTransport,
+): BashOperations {
+  return {
+    exec: (command, _factoryCwd, { onData, signal, timeout }) => {
+      if (!connection.remoteCwd.startsWith("/")) {
+        throw new Error(`ssh_bash requires an absolute remote cwd, received '${connection.remoteCwd}'`);
+      }
+      return transport.exec(command, connection.remoteCwd, { onData, signal, timeout });
+    },
+  };
+}