chore(testing): add unit tests and update core render/network pipelines

- add new tests:
  - test_blp_loader.cpp
  - test_dbc_loader.cpp
  - test_entity.cpp
  - test_frustum.cpp
  - test_m2_structs.cpp
  - test_opcode_table.cpp
  - test_packet.cpp
  - test_srp.cpp
  - CMakeLists.txt
- add docs and progress tracking:
  - TESTING.md
  - perf_baseline.md
- update project config/build:
  - .gitignore
  - CMakeLists.txt
  - test.sh
- core engine updates:
  - application.cpp
  - game_handler.cpp
  - world_socket.cpp
  - adt_loader.cpp
  - asset_manager.cpp
  - m2_renderer.cpp
  - post_process_pipeline.cpp
  - renderer.cpp
  - terrain_manager.cpp
  - game_screen.cpp
- add profiler header:
  - profiler.hpp

tests/test_entity.cpp

@@ -0,0 +1,220 @@
+// Phase 0 – Entity, Unit, Player, GameObject, EntityManager tests
+#include <catch_amalgamated.hpp>
+#include "game/entity.hpp"
+#include <memory>
+
+using namespace wowee::game;
+
+TEST_CASE("Entity default construction", "[entity]") {
+    Entity e;
+    REQUIRE(e.getGuid() == 0);
+    REQUIRE(e.getType() == ObjectType::OBJECT);
+    REQUIRE(e.getX() == 0.0f);
+    REQUIRE(e.getY() == 0.0f);
+    REQUIRE(e.getZ() == 0.0f);
+    REQUIRE(e.getOrientation() == 0.0f);
+}
+
+TEST_CASE("Entity GUID constructor", "[entity]") {
+    Entity e(0xDEADBEEF);
+    REQUIRE(e.getGuid() == 0xDEADBEEF);
+}
+
+TEST_CASE("Entity position set/get", "[entity]") {
+    Entity e;
+    e.setPosition(1.0f, 2.0f, 3.0f, 1.57f);
+    REQUIRE(e.getX() == Catch::Approx(1.0f));
+    REQUIRE(e.getY() == Catch::Approx(2.0f));
+    REQUIRE(e.getZ() == Catch::Approx(3.0f));
+    REQUIRE(e.getOrientation() == Catch::Approx(1.57f));
+}
+
+TEST_CASE("Entity field set/get/has", "[entity]") {
+    Entity e;
+    REQUIRE_FALSE(e.hasField(10));
+
+    e.setField(10, 0xCAFE);
+    REQUIRE(e.hasField(10));
+    REQUIRE(e.getField(10) == 0xCAFE);
+
+    // Overwrite
+    e.setField(10, 0xBEEF);
+    REQUIRE(e.getField(10) == 0xBEEF);
+
+    // Non-existent returns 0
+    REQUIRE(e.getField(999) == 0);
+}
+
+TEST_CASE("Unit construction and type", "[entity]") {
+    Unit u;
+    REQUIRE(u.getType() == ObjectType::UNIT);
+
+    Unit u2(0x123);
+    REQUIRE(u2.getGuid() == 0x123);
+    REQUIRE(u2.getType() == ObjectType::UNIT);
+}
+
+TEST_CASE("Unit name", "[entity]") {
+    Unit u;
+    REQUIRE(u.getName().empty());
+    u.setName("Hogger");
+    REQUIRE(u.getName() == "Hogger");
+}
+
+TEST_CASE("Unit health", "[entity]") {
+    Unit u;
+    REQUIRE(u.getHealth() == 0);
+    REQUIRE(u.getMaxHealth() == 0);
+
+    u.setHealth(500);
+    u.setMaxHealth(1000);
+    REQUIRE(u.getHealth() == 500);
+    REQUIRE(u.getMaxHealth() == 1000);
+}
+
+TEST_CASE("Unit power by type", "[entity]") {
+    Unit u;
+    u.setPowerType(0); // mana
+    u.setPower(200);
+    u.setMaxPower(500);
+
+    REQUIRE(u.getPower() == 200);
+    REQUIRE(u.getMaxPower() == 500);
+    REQUIRE(u.getPowerByType(0) == 200);
+    REQUIRE(u.getMaxPowerByType(0) == 500);
+
+    // Set rage (type 1)
+    u.setPowerByType(1, 50);
+    u.setMaxPowerByType(1, 100);
+    REQUIRE(u.getPowerByType(1) == 50);
+    REQUIRE(u.getMaxPowerByType(1) == 100);
+
+    // Out of bounds clamps
+    REQUIRE(u.getPowerByType(7) == 0);
+    REQUIRE(u.getMaxPowerByType(7) == 0);
+}
+
+TEST_CASE("Unit level, entry, displayId", "[entity]") {
+    Unit u;
+    REQUIRE(u.getLevel() == 1); // default
+    u.setLevel(80);
+    REQUIRE(u.getLevel() == 80);
+
+    u.setEntry(1234);
+    REQUIRE(u.getEntry() == 1234);
+
+    u.setDisplayId(5678);
+    REQUIRE(u.getDisplayId() == 5678);
+}
+
+TEST_CASE("Unit flags", "[entity]") {
+    Unit u;
+    u.setUnitFlags(0x01);
+    REQUIRE(u.getUnitFlags() == 0x01);
+
+    u.setDynamicFlags(0x02);
+    REQUIRE(u.getDynamicFlags() == 0x02);
+
+    u.setNpcFlags(0x04);
+    REQUIRE(u.getNpcFlags() == 0x04);
+    REQUIRE(u.isInteractable());
+
+    u.setNpcFlags(0);
+    REQUIRE_FALSE(u.isInteractable());
+}
+
+TEST_CASE("Unit faction and hostility", "[entity]") {
+    Unit u;
+    u.setFactionTemplate(14); // Undercity
+    REQUIRE(u.getFactionTemplate() == 14);
+
+    REQUIRE_FALSE(u.isHostile());
+    u.setHostile(true);
+    REQUIRE(u.isHostile());
+}
+
+TEST_CASE("Unit mount display ID", "[entity]") {
+    Unit u;
+    REQUIRE(u.getMountDisplayId() == 0);
+    u.setMountDisplayId(14374);
+    REQUIRE(u.getMountDisplayId() == 14374);
+}
+
+TEST_CASE("Player inherits Unit", "[entity]") {
+    Player p(0xABC);
+    REQUIRE(p.getType() == ObjectType::PLAYER);
+    REQUIRE(p.getGuid() == 0xABC);
+
+    // Player inherits Unit name — regression test for the shadowed-field fix
+    p.setName("Arthas");
+    REQUIRE(p.getName() == "Arthas");
+
+    p.setLevel(80);
+    REQUIRE(p.getLevel() == 80);
+}
+
+TEST_CASE("GameObject construction", "[entity]") {
+    GameObject go(0x999);
+    REQUIRE(go.getType() == ObjectType::GAMEOBJECT);
+    REQUIRE(go.getGuid() == 0x999);
+
+    go.setName("Mailbox");
+    REQUIRE(go.getName() == "Mailbox");
+
+    go.setEntry(42);
+    REQUIRE(go.getEntry() == 42);
+
+    go.setDisplayId(100);
+    REQUIRE(go.getDisplayId() == 100);
+}
+
+TEST_CASE("EntityManager add/get/has/remove", "[entity]") {
+    EntityManager mgr;
+    REQUIRE(mgr.getEntityCount() == 0);
+
+    auto unit = std::make_shared<Unit>(1);
+    unit->setName("TestUnit");
+    mgr.addEntity(1, unit);
+
+    REQUIRE(mgr.getEntityCount() == 1);
+    REQUIRE(mgr.hasEntity(1));
+    REQUIRE_FALSE(mgr.hasEntity(2));
+
+    auto retrieved = mgr.getEntity(1);
+    REQUIRE(retrieved != nullptr);
+    REQUIRE(retrieved->getGuid() == 1);
+
+    mgr.removeEntity(1);
+    REQUIRE_FALSE(mgr.hasEntity(1));
+    REQUIRE(mgr.getEntityCount() == 0);
+}
+
+TEST_CASE("EntityManager clear", "[entity]") {
+    EntityManager mgr;
+    mgr.addEntity(1, std::make_shared<Entity>(1));
+    mgr.addEntity(2, std::make_shared<Entity>(2));
+    REQUIRE(mgr.getEntityCount() == 2);
+
+    mgr.clear();
+    REQUIRE(mgr.getEntityCount() == 0);
+}
+
+TEST_CASE("EntityManager null entity rejected", "[entity]") {
+    EntityManager mgr;
+    mgr.addEntity(1, nullptr);
+    // Null should be rejected (logged warning, not stored)
+    REQUIRE(mgr.getEntityCount() == 0);
+}
+
+TEST_CASE("EntityManager getEntities returns all", "[entity]") {
+    EntityManager mgr;
+    mgr.addEntity(10, std::make_shared<Unit>(10));
+    mgr.addEntity(20, std::make_shared<Player>(20));
+    mgr.addEntity(30, std::make_shared<GameObject>(30));
+
+    const auto& all = mgr.getEntities();
+    REQUIRE(all.size() == 3);
+    REQUIRE(all.count(10) == 1);
+    REQUIRE(all.count(20) == 1);
+    REQUIRE(all.count(30) == 1);
+}