fix(config): preserve existing nested state dir before short-circuiting

When OPENCLAW_HOME basename matches a known state dir name, the
nesting guard in resolveStateDir now checks whether a nested .openclaw
subdirectory already exists before returning the parent. This preserves
backward compatibility for installs that previously wrote state data
into the (now-prevented) nested path.

Mirrors the same fix already applied to resolveConfigDir in utils.ts.

src/config/paths.test.ts

@@ -1,6 +1,7 @@
 import fs from "node:fs/promises";
+import fsSync from "node:fs";
 import path from "node:path";
-import { describe, expect, it } from "vitest";
+import { describe, expect, it, vi } from "vitest";
 import { withTempDir } from "../test-helpers/temp-dir.js";
 import {
   resolveDefaultConfigCandidates,
@@ -172,4 +173,12 @@ describe("resolveStateDir nesting guard (#45765)", () => {
     const env = { HOME: "/home/user" } as NodeJS.ProcessEnv;
     expect(resolveStateDir(env)).toBe(path.resolve("/home/user/.openclaw"));
   });
+
+  it("preserves existing nested state dir for backward compat", () => {
+    const env = { OPENCLAW_HOME: "/home/user/.openclaw" } as NodeJS.ProcessEnv;
+    const nestedDir = path.resolve("/home/user/.openclaw/.openclaw");
+    vi.spyOn(fsSync, "existsSync").mockImplementation((p) => String(p) === nestedDir);
+    expect(resolveStateDir(env)).toBe(nestedDir);
+    vi.restoreAllMocks();
+  });
 });

src/config/paths.ts

@@ -78,6 +78,16 @@ export function resolveStateDir(
   if (explicitHome) {
     const resolvedHome = effectiveHomedir();
     if (ALL_STATE_DIRNAMES.has(path.basename(resolvedHome))) {
+      // Backward compat: if a nested state dir already exists from the old
+      // buggy behavior, prefer it so we don't orphan existing state data.
+      const nestedState = path.join(resolvedHome, ".openclaw");
+      try {
+        if (fs.existsSync(nestedState)) {
+          return nestedState;
+        }
+      } catch {
+        // best-effort
+      }
       return resolvedHome;
     }
   }