Standardize naming conventions (#12)

## Summary

Standardize naming conventions across the entire wizapp-stdlib codebase by replacing inconsistent prefixes and snake_case with a unified `wp` prefix + CamelCase scheme.

## Changes

### Naming convention applied

| Pattern | Before | After |
|---|---|---|
| Public functions | `wapp_module_function` | `wpModuleFunction` |
| Public types | `GenericXxx`, bare `Xxx` | `WpXxx` |
| Constants / enum values | `WAPP_XXX`, `SHELL_XXX` | `WP_XXX`, `WP_SHELL_XXX` |
| Internal functions | `_module_function` | `_moduleFunction` |
| Storage-class macros | `wapp_extern`, `wapp_intern` | `wp_extern`, `wp_intern` |

### Modules affected

All 20 modules were renamed: `arena`, `array`, `dbl_list`, `queue`, `str8`, `mem_allocator`, `mem_utils`, `mem_os`, `file`, `cpath`, `log`, `shell_commander`, `shell_termcolour`, `shell_utils`, `prng/xorshift`, `uuid`, `tester`, `aliases`, `assert`, `misc_utils`, `platform` — plus their test files.

### Backward compatibility

Added `src/oldnames.h` with `#define OLD_NAME NEW_NAME` for every renamed symbol, organized by module under Constants → Types → Functions sections. Existing code that includes this file will compile without changes.

Reviewed-on: #12
Co-authored-by: Abdelrahman <said.abdelrahman89@gmail.com>
Co-committed-by: Abdelrahman <said.abdelrahman89@gmail.com>

src/os/file/win/file_win.h

@@ -6,26 +6,26 @@
 #include "../../../common/aliases/aliases.h"
 #include "../../../common/platform/platform.h"
 
-#ifdef WAPP_PLATFORM_CPP
+#ifdef WP_PLATFORM_CPP
 BEGIN_C_LINKAGE
-#endif // !WAPP_PLATFORM_CPP
+#endif // !WP_PLATFORM_CPP
 
-#ifdef WAPP_PLATFORM_WINDOWS
+#ifdef WP_PLATFORM_WINDOWS
 
-#define END_OF_LINE "\r\n"
+#define WP_END_OF_LINE "\r\n"
 
 #define WIN32_LEAN_AND_MEAN
 #include <Windows.h>
 #include <fileapi.h>
 
-struct WFile {
+struct WpFile {
 	HANDLE fh;
 };
 
-#endif // !WAPP_PLATFORM_WINDOWS
+#endif // !WP_PLATFORM_WINDOWS
 
-#ifdef WAPP_PLATFORM_CPP
+#ifdef WP_PLATFORM_CPP
 END_C_LINKAGE
-#endif // !WAPP_PLATFORM_CPP
+#endif // !WP_PLATFORM_CPP
 
 #endif // !FILE_WIN_H