Add Borealis GUI for patch extraction on Switch.

Replace the console UI with a Borealis-based flow, bundle ROMFS assets and
borealis as a submodule, and apply small upstream patches at build time.
Self-delete runs after romfsExit on quit so the NRO can be removed like the
old console build.

source/extractor.cpp

@@ -0,0 +1,134 @@
+#include "extractor.hpp"
+
+#include <cstdio>
+#include <cstring>
+#include <sys/stat.h>
+
+#ifdef __SWITCH__
+#include <switch.h>
+#endif
+
+static constexpr size_t READ_BUF_SIZE = 8192;
+
+int PatchExtractor::mkdirs(const char* path) {
+    char tmp[512];
+    snprintf(tmp, sizeof(tmp), "%s", path);
+    size_t len = strlen(tmp);
+    if (len == 0) return 0;
+    if (tmp[len - 1] == '/') tmp[len - 1] = '\0';
+
+    for (char* p = tmp + 1; *p; p++) {
+        if (*p == '/') {
+            *p = '\0';
+            mkdir(tmp, 0755);
+            *p = '/';
+        }
+    }
+    return mkdir(tmp, 0755);
+}
+
+bool PatchExtractor::open() {
+    zip = unzOpen(PATCHES_ZIP);
+    if (!zip) return false;
+
+    unz_global_info gi{};
+    if (unzGetGlobalInfo(zip, &gi) != UNZ_OK) {
+        close();
+        return false;
+    }
+
+    total     = gi.number_entry;
+    extracted = 0;
+    skipped   = 0;
+    finished  = false;
+    err       = unzGoToFirstFile(zip);
+    return true;
+}
+
+void PatchExtractor::close() {
+    if (zip) {
+        unzClose(zip);
+        zip = nullptr;
+    }
+}
+
+int PatchExtractor::getProgressPercent() const {
+    if (total == 0) return 100;
+    return static_cast<int>((extracted * 100) / total);
+}
+
+bool PatchExtractor::step() {
+    if (!zip || finished) return false;
+
+    if (err != UNZ_OK) {
+        finished = true;
+        return false;
+    }
+
+    char filename[512];
+    char fullpath[1024];
+    unz_file_info fi{};
+
+    unzGetCurrentFileInfo(zip, &fi, filename, sizeof(filename), nullptr, 0, nullptr, 0);
+    snprintf(fullpath, sizeof(fullpath), "%s%s", EXTRACT_DIR, filename);
+    currentFile = filename;
+
+    size_t flen = strlen(filename);
+    if (flen > 0 && filename[flen - 1] == '/') {
+        mkdirs(fullpath);
+    } else {
+        char dirpart[1024];
+        snprintf(dirpart, sizeof(dirpart), "%s", fullpath);
+        char* last_slash = strrchr(dirpart, '/');
+        if (last_slash) {
+            *last_slash = '\0';
+            mkdirs(dirpart);
+        }
+
+        if (unzOpenCurrentFile(zip) == UNZ_OK) {
+            FILE* out = fopen(fullpath, "wb");
+            if (out) {
+                unsigned char buf[READ_BUF_SIZE];
+                int bytes;
+                while ((bytes = unzReadCurrentFile(zip, buf, READ_BUF_SIZE)) > 0) {
+                    fwrite(buf, 1, static_cast<size_t>(bytes), out);
+                }
+                fclose(out);
+            } else {
+                skipped++;
+            }
+            unzCloseCurrentFile(zip);
+        } else {
+            skipped++;
+        }
+    }
+
+    extracted++;
+    err = unzGoToNextFile(zip);
+    if (err != UNZ_OK) finished = true;
+
+    return !finished;
+}
+
+bool PatchExtractor::cleanup() {
+    cleanupOk_ = true;
+
+    if (remove(PATCHES_ZIP) != 0)
+        cleanupOk_ = false;
+
+    // Cannot delete our own NRO while the app is still running; try anyway for edge cases.
+    remove(SELF_NRO);
+
+    remove("sdmc:/switch/.PatchExtractor.nro.star");
+    remove("sdmc:/switch/.packages/boot_package.ini");
+
+    return cleanupOk_;
+}
+
+void PatchExtractor::tryDeleteSelfOnExit() {
+#ifdef __SWITCH__
+    // Embedded ROMFS keeps the .nro open on SD; unmount before unlink (console build had no ROMFS).
+    romfsExit();
+#endif
+    remove(SELF_NRO);
+}