Fix the build after archiving rpg/ui/scene: drop their last live dependents

rpg/ui/scene moved to archive/ earlier left a handful of otherwise-generic
systems with dead references into them:
- asset/loader/chunk existed solely to load rpg overworld map chunks
  (tile_t, worldpos_t) - deleted outright, along with its
  ASSET_LOADER_TYPE_CHUNK entry in assetloader.c/h.
- save/slot wrapped party_t/storyflagval_t/map-name/cutscene-path, which is
  100% rpg save data - deleted outright (save.c/h, savedevice.c/h and the
  Linux save backend keep their generic settings/device-discovery logic,
  just lose the slot read/write pieces that only existed for it).
- locale/localemanager.c and test/CMakeLists.txt/test/save/* had a few
  stray includes and test cases that only existed for the now-gone code.

Also restores assets/locale/en_US.po (copied back from archive/assets/) -
locale init still needs a real locale file to boot into, even with the
asset-moving/archiving done separately.

Co-Authored-By: Claude Sonnet 5 <[email protected]>

test/save/test_savedevice.c

@@ -8,9 +8,7 @@
 #include "dusktest.h"
 #include "savetestfixture.h"
 #include "save/savedevice.h"
-#include "save/slot/saveslot.h"
 #include "save/settings/savesettings.h"
-#include "save/save.h"
 #include "util/memory.h"
 #include "util/string.h"
 
@@ -150,28 +148,10 @@ static void test_saveDeviceCheckAvailability_resolvesSynchronouslyOnLinux(
 }
 
 // ============================================================
-// saveDeviceSlotWrite / saveDeviceSlotRead / saveDeviceSettingsWrite /
-// saveDeviceSettingsRead - dispatch to the platform's four hooks.
+// saveDeviceSettingsWrite / saveDeviceSettingsRead - dispatch to the
+// platform's hooks.
 // ============================================================
 
-static void test_saveDeviceSlotWrite_nullAsserts(void **state) {
-  savedevice_t device;
-  // Content is never touched - both calls assert on a NULL argument
-  // before either device or slot would actually be read.
-  saveslot_t slot;
-
-  expect_assert_failure(saveDeviceSlotWrite(NULL, &slot, 0));
-  expect_assert_failure(saveDeviceSlotWrite(&device, NULL, 0));
-}
-
-static void test_saveDeviceSlotRead_nullAsserts(void **state) {
-  savedevice_t device;
-  saveslot_t slot;
-
-  expect_assert_failure(saveDeviceSlotRead(NULL, &slot, 0));
-  expect_assert_failure(saveDeviceSlotRead(&device, NULL, 0));
-}
-
 static void test_saveDeviceSettingsWrite_nullAsserts(void **state) {
   savedevice_t device;
   savesettings_t settings;
@@ -190,32 +170,6 @@ static void test_saveDeviceSettingsRead_nullAsserts(void **state) {
   expect_assert_failure(saveDeviceSettingsRead(&device, NULL));
 }
 
-static void test_saveDeviceSlot_dispatchesToPlatform(void **state) {
-  savedevice_t device;
-  errorret_t initRet = saveDeviceInit(&device);
-  assert_true(errorIsOk(initRet));
-  // The save directory must exist before a write can succeed - normally
-  // saveDeviceCheckAvailability does this via the platform's mkdirp.
-  saveDeviceCheckAvailability(&device, updateCallback, NULL);
-  saveDeviceUpdate(&device);
-
-  // saveSlotInit() only ever operates on SAVE.slot now, so that's the
-  // write source here.
-  saveSlotInit(&SAVE.slot);
-  SAVE.slot.cachedData.playerLevel = 21;
-
-  errorret_t writeRet = saveDeviceSlotWrite(&device, &SAVE.slot, 0);
-  assert_true(errorIsOk(writeRet));
-
-  // No pre-init needed - saveSlotReadJSON() (via saveDeviceSlotRead) fully
-  // resets/overwrites its destination struct regardless of prior content.
-  saveslot_t read;
-  errorret_t readRet = saveDeviceSlotRead(&device, &read, 0);
-  assert_true(errorIsOk(readRet));
-
-  assert_int_equal(read.cachedData.playerLevel, 21);
-}
-
 static void test_saveDeviceSettings_dispatchesToPlatform(void **state) {
   savedevice_t device;
   errorret_t initRet = saveDeviceInit(&device);
@@ -303,14 +257,6 @@ int main(void) {
       saveTestFixtureSetup, saveTestFixtureTeardown
     ),
 
-    cmocka_unit_test_setup_teardown(
-      test_saveDeviceSlotWrite_nullAsserts,
-      saveTestFixtureSetup, saveTestFixtureTeardown
-    ),
-    cmocka_unit_test_setup_teardown(
-      test_saveDeviceSlotRead_nullAsserts,
-      saveTestFixtureSetup, saveTestFixtureTeardown
-    ),
     cmocka_unit_test_setup_teardown(
       test_saveDeviceSettingsWrite_nullAsserts,
       saveTestFixtureSetup, saveTestFixtureTeardown
@@ -319,10 +265,6 @@ int main(void) {
       test_saveDeviceSettingsRead_nullAsserts,
       saveTestFixtureSetup, saveTestFixtureTeardown
     ),
-    cmocka_unit_test_setup_teardown(
-      test_saveDeviceSlot_dispatchesToPlatform,
-      saveTestFixtureSetup, saveTestFixtureTeardown
-    ),
     cmocka_unit_test_setup_teardown(
       test_saveDeviceSettings_dispatchesToPlatform,
       saveTestFixtureSetup, saveTestFixtureTeardown