feat(editor): add --rename-by-magic extension recovery flag

Reads the 4-byte magic of a file, looks it up in the shared
format table, and renames the file to use the correct .w*
extension. Useful when files have lost their extensions
(downloaded as 'data.bin', extracted from a tarball with
mangled metadata, or copied via a tool that strips suffixes).

Safe by default — refuses to overwrite an existing target;
pass --force to allow overwrite. --dry-run prints the planned
move without touching the filesystem. Files that already have
the correct extension are a no-op. Unrecognized magic exits
1 with the bytes printed for diagnostic context.

Reuses cli_format_table.cpp so any future format addition is
picked up automatically.

tools/editor/cli_rename_magic.cpp

@@ -0,0 +1,101 @@
+#include "cli_rename_magic.hpp"
+#include "cli_arg_parse.hpp"
+#include "cli_format_table.hpp"
+
+#include <cstdint>
+#include <cstdio>
+#include <cstring>
+#include <filesystem>
+#include <fstream>
+#include <string>
+
+namespace wowee {
+namespace editor {
+namespace cli {
+
+namespace {
+
+namespace fs = std::filesystem;
+
+bool readMagic(const fs::path& path, char magic[4]) {
+    std::ifstream is(path, std::ios::binary);
+    if (!is) return false;
+    is.read(magic, 4);
+    return is.gcount() == 4;
+}
+
+int handleRename(int& i, int argc, char** argv) {
+    std::string filePath = argv[++i];
+    bool dryRun = false;
+    bool force = false;
+    while (i + 1 < argc) {
+        std::string a = argv[i + 1];
+        if (a == "--dry-run") { dryRun = true; ++i; }
+        else if (a == "--force") { force = true; ++i; }
+        else break;
+    }
+    fs::path src = filePath;
+    if (!fs::exists(src) || !fs::is_regular_file(src)) {
+        std::fprintf(stderr,
+            "rename-by-magic: not a file: %s\n", filePath.c_str());
+        return 1;
+    }
+    char magic[4];
+    if (!readMagic(src, magic)) {
+        std::fprintf(stderr,
+            "rename-by-magic: cannot read 4-byte magic: %s\n",
+            filePath.c_str());
+        return 1;
+    }
+    const FormatMagicEntry* fmt = findFormatByMagic(magic);
+    if (!fmt) {
+        char magicStr[5] = {magic[0], magic[1], magic[2], magic[3], 0};
+        std::fprintf(stderr,
+            "rename-by-magic: unrecognized magic '%s' in %s\n",
+            magicStr, filePath.c_str());
+        return 1;
+    }
+    fs::path dst = src;
+    dst.replace_extension(fmt->extension);
+    if (src == dst) {
+        std::printf("rename-by-magic: %s already has correct "
+                     "extension (%s) — no change\n",
+                     filePath.c_str(), fmt->extension);
+        return 0;
+    }
+    if (fs::exists(dst) && !force) {
+        std::fprintf(stderr,
+            "rename-by-magic: target %s already exists "
+            "(pass --force to overwrite)\n", dst.string().c_str());
+        return 1;
+    }
+    if (dryRun) {
+        std::printf("rename-by-magic (dry-run): %s -> %s\n",
+                     filePath.c_str(), dst.string().c_str());
+        return 0;
+    }
+    std::error_code ec;
+    fs::rename(src, dst, ec);
+    if (ec) {
+        std::fprintf(stderr,
+            "rename-by-magic: rename failed: %s\n",
+            ec.message().c_str());
+        return 1;
+    }
+    std::printf("rename-by-magic: %s -> %s\n",
+                 filePath.c_str(), dst.string().c_str());
+    return 0;
+}
+
+} // namespace
+
+bool handleRenameMagic(int& i, int argc, char** argv, int& outRc) {
+    if (std::strcmp(argv[i], "--rename-by-magic") == 0 && i + 1 < argc) {
+        outRc = handleRename(i, argc, argv); return true;
+    }
+    return false;
+}
+
+} // namespace cli
+} // namespace editor
+} // namespace wowee