feat(omp): list ssh:// directories via read

- `read ssh://host/dir` lists a remote directory one level deep; `ssh://host/` lists the remote root
- add statRemotePath + listRemoteDir; resolve reads first and classifies on error (directory -> one-level listing, dirs-first, dotfiles included)
- directory resources carry isDirectory + immutable and expose no sourcePath
- search refuses a virtual (no-sourcePath) directory resource instead of grepping the listing text
- writeRemoteFile refuses a directory destination and cleans up its temp on that path

packages/coding-agent/src/ssh/__tests__/file-transfer-posix-guard.test.ts

@@ -0,0 +1,29 @@
+import { afterEach, describe, expect, it, vi } from "bun:test";
+import type { SSHConnectionTarget } from "../connection-manager";
+import * as connectionManager from "../connection-manager";
+import { readRemoteFile, writeRemoteFile } from "../file-transfer";
+
+describe("ssh file-transfer POSIX guard", () => {
+	afterEach(() => {
+		vi.restoreAllMocks();
+	});
+
+	it("rejects a confirmed Windows remote before running any POSIX command", async () => {
+		// Stub BOTH the connection and the host-info probe so the guard is reached
+		// without opening a real SSH connection and before any command is spawned.
+		const ensureConnectionSpy = vi.spyOn(connectionManager, "ensureConnection").mockResolvedValue(undefined);
+		const ensureHostInfoSpy = vi.spyOn(connectionManager, "ensureHostInfo").mockResolvedValue({
+			version: 2,
+			os: "windows",
+			shell: "powershell",
+			compatEnabled: false,
+		});
+		const target: SSHConnectionTarget = { name: "winbox", host: "winbox" };
+		await expect(readRemoteFile(target, "C:/x.txt", { maxBytes: 1024 })).rejects.toThrow(/Windows host/);
+		await expect(writeRemoteFile(target, "C:/x.txt", new Uint8Array([1]), {})).rejects.toThrow(/Windows host/);
+		// Prove the guard ran through the stubbed transport rather than failing early
+		// for an unrelated reason (e.g. a future import refactor bypassing the mocks).
+		expect(ensureConnectionSpy).toHaveBeenCalled();
+		expect(ensureHostInfoSpy).toHaveBeenCalled();
+	});
+});