custom models: envmap support (#3777)

Custom models and model replacements now support environment mapping.

Also fixed some cases in Jak 3 where tfrags had missing textures
(defaulting to texture 0 from tpage 0, which in Jak 3 is the default eye
texture) and replaced them with more suitable alternatives.

Fixes #3776 


https://github.com/user-attachments/assets/7c11b0de-b254-40cb-9719-11238dfb3d43


![image](https://github.com/user-attachments/assets/4cc60b55-4965-4cb8-b29d-096560e7b3aa)


![image](https://github.com/user-attachments/assets/cb46d0d1-57d7-482c-b235-15d0e633f62c)

decompiler/level_extractor/extract_tfrag.cpp

@@ -2032,6 +2032,20 @@ s32 find_or_add_texture_to_level(u32 combo_tex_id,
       if (ok_to_miss) {
         // we're missing a texture, just use the first one.
         tex_it = tdb.textures.begin();
+        // some tfrags in jak 3 are missing textures, so we use some suitable
+        // replacements instead of the default eye texture
+        static std::map<std::string, std::string> per_level_tex_hacks = {
+            {"wasintro", "des-rock-01"},
+            {"intpfall", "common-black"},
+            {"powergd", "common-black"},
+        };
+        auto it = std::find_if(tdb.textures.begin(), tdb.textures.end(),
+                               [&](const std::pair<u32, TextureDB::TextureData> val) {
+                                 return val.second.name == per_level_tex_hacks[level_name];
+                               });
+        if (it != tdb.textures.end()) {
+          tex_it = it;
+        }
       } else {
         ASSERT_MSG(
             false,