test(cli): integration tests for edit/history, attachments, settings

Adds RELICARIO_TEST_ITEM_SECRET env hatch for rpassword calls in
cmd_add / cmd_edit so piped-stdin tests can exercise the password
prompt paths without a TTY.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

crates/relicario-cli/tests/settings.rs

@@ -0,0 +1,23 @@
+mod common;
+
+use common::TestVault;
+
+#[test]
+fn settings_roundtrip_trash_retention() {
+    let v = TestVault::init();
+    let out = v.run(&["settings", "show"]);
+    assert!(String::from_utf8(out.stdout).unwrap().contains("trash_retention"));
+
+    let out = v.run(&["settings", "trash-retention", "--days", "60"]);
+    assert!(out.status.success(), "set failed: {:?}", out);
+    let out = v.run(&["settings", "show"]);
+    let stdout = String::from_utf8(out.stdout).unwrap();
+    assert!(stdout.contains("60"), "expected 60: {stdout}");
+}
+
+#[test]
+fn settings_rejects_conflicting_retention_flags() {
+    let v = TestVault::init();
+    let out = v.run(&["settings", "trash-retention", "--days", "30", "--forever"]);
+    assert!(!out.status.success());
+}