render entities from vanilla client models, add items, displays and leashes

- dump entity models straight from the unobfuscated client jar
  (tools/VanillaModelDump.java, tools/update-vanilla-models.sh): models posed
  by vanilla setupAnim, baby/variant/layer models, renderer transforms,
  default textures, pose variants (sitting, holding items, illager arms)
  and all layer definitions; the old CEM template is only a fallback now
- fix adult zombies captured as babies, zero-thickness planes (wings,
  fins) and back faces in the entity intersector
- held items, head items (pumpkins, skulls), shields, elytra, saddles and
  body equipment for every mount, armor following the pose
- block/item/text display entities, dropped items, falling blocks, primed
  TNT, minecart contents, block entities inside displays, leash ropes
- item models resolved from the 26.x item definitions with display
  transforms; generated items extruded like vanilla
- bundle the vanilla font definitions as fallback so sign/text rendering
  works with packs that lack font/*.json
- one failing entity no longer aborts the whole photo
- edge-case test plugin (tools/edgecase-plugin) and offline harnesses

src/main/java/eu/mhsl/minecraft/pixelpics/Main.java

@@ -107,6 +107,20 @@ public final class Main extends JavaPlugin {
         } catch (Exception e) {
             getLogger().severe("Failed to load CEM entity models: " + e.getMessage());
         }
+        // Vanilla models dumped from the client jar (tools/VanillaModelDump.java) override the CEM set: an
+        // optional newer dump in the data folder (no recompile on MC updates), else the bundled copy.
+        File dump = new File(getDataFolder(), "vanilla_entity_models.json");
+        try (InputStream in =
+                dump.isFile() ? new java.io.FileInputStream(dump) : getResource("cem/vanilla_entity_models.json")) {
+            if (in != null) {
+                int n = cemLoader.load(in, getLogger());
+                getLogger()
+                        .info("Loaded vanilla entity models" + (dump.isFile() ? " from " + dump.getName() : "") + " ("
+                                + n + " models total).");
+            }
+        } catch (Exception e) {
+            getLogger().severe("Failed to load vanilla entity models: " + e.getMessage());
+        }
         SkinCache skinCache = new SkinCache();
         BitmapFont font = FontLoader.load(resourcePack, textures, getLogger());
         getLogger().info("Loaded sign font (" + (font.isEmpty() ? "no glyphs — text disabled" : "ok") + ").");