fix(tests): isolate CLAW_CONFIG_HOME in resumed_status JSON test

resumed_status_command_emits_structured_json_when_requested was reading
the real ~/.claw/settings.json, causing loaded_config_files to be 1
instead of the expected 0 on machines with user config present.

Root cause: unlike other tests (e.g. resumed_config_command_loads_settings_files),
this test did not pass an isolated CLAW_CONFIG_HOME env var to run_claw,
so claw fell back to the real HOME and loaded the developer's settings file.

Fix: create a temp config-home dir and pass it as CLAW_CONFIG_HOME via
run_claw_with_env. This gives the assertion a clean 0-file baseline.

Unblocks PRs #2973, #2988, #2990 which all failed this same test on main.

Ref: ROADMAP #65

rust/crates/rusty-claude-cli/tests/resume_slash_commands.rs

@@ -227,6 +227,8 @@ fn resumed_status_command_emits_structured_json_when_requested() {
     // given
     let temp_dir = unique_temp_dir("resume-status-json");
     fs::create_dir_all(&temp_dir).expect("temp dir should exist");
+    let config_home = temp_dir.join("config-home");
+    fs::create_dir_all(&config_home).expect("isolated config home should exist");
     let session_path = temp_dir.join("session.jsonl");
 
     let mut session = workspace_session(&temp_dir);
@@ -238,7 +240,9 @@ fn resumed_status_command_emits_structured_json_when_requested() {
         .expect("session should persist");
 
     // when
-    let output = run_claw(
+    // Use an isolated CLAW_CONFIG_HOME so ~/.claw/settings.json is not loaded,
+    // which would cause loaded_config_files to be non-zero (#65).
+    let output = run_claw_with_env(
         &temp_dir,
         &[
             "--output-format",
@@ -247,6 +251,7 @@ fn resumed_status_command_emits_structured_json_when_requested() {
             session_path.to_str().expect("utf8 path"),
             "/status",
         ],
+        &[("CLAW_CONFIG_HOME", config_home.to_str().expect("utf8 path"))],
     );
 
     // then