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_opcode_table.cpp

@@ -0,0 +1,118 @@
+// Phase 0 – OpcodeTable load from JSON, toWire/fromWire mapping
+#include <catch_amalgamated.hpp>
+#include "game/opcode_table.hpp"
+#include <fstream>
+#include <filesystem>
+#include <cstdio>
+
+using wowee::game::OpcodeTable;
+using wowee::game::LogicalOpcode;
+
+// Helper: write a temporary JSON file and return its path.
+// Uses the executable's directory to avoid permission issues.
+static std::string writeTempJson(const std::string& content) {
+    auto path = std::filesystem::temp_directory_path() / "wowee_test_opcodes.json";
+    std::ofstream f(path);
+    f << content;
+    f.close();
+    return path.string();
+}
+
+TEST_CASE("OpcodeTable loadFromJson basic mapping", "[opcode_table]") {
+    // CMSG_PING and SMSG_PONG are canonical opcodes present in the generated enum.
+    std::string json = R"({
+        "CMSG_PING": "0x1DC",
+        "SMSG_PONG": "0x1DD"
+    })";
+    auto path = writeTempJson(json);
+
+    OpcodeTable table;
+    REQUIRE(table.loadFromJson(path));
+
+    REQUIRE(table.size() == 2);
+    REQUIRE(table.hasOpcode(LogicalOpcode::CMSG_PING));
+    REQUIRE(table.toWire(LogicalOpcode::CMSG_PING) == 0x1DC);
+    REQUIRE(table.toWire(LogicalOpcode::SMSG_PONG) == 0x1DD);
+
+    std::remove(path.c_str());
+}
+
+TEST_CASE("OpcodeTable fromWire reverse lookup", "[opcode_table]") {
+    std::string json = R"({ "CMSG_PING": "0x1DC" })";
+    auto path = writeTempJson(json);
+
+    OpcodeTable table;
+    table.loadFromJson(path);
+
+    auto result = table.fromWire(0x1DC);
+    REQUIRE(result.has_value());
+    REQUIRE(*result == LogicalOpcode::CMSG_PING);
+
+    std::remove(path.c_str());
+}
+
+TEST_CASE("OpcodeTable unknown wire returns nullopt", "[opcode_table]") {
+    std::string json = R"({ "CMSG_PING": "0x1DC" })";
+    auto path = writeTempJson(json);
+
+    OpcodeTable table;
+    table.loadFromJson(path);
+
+    auto result = table.fromWire(0x9999);
+    REQUIRE_FALSE(result.has_value());
+
+    std::remove(path.c_str());
+}
+
+TEST_CASE("OpcodeTable unknown logical returns 0xFFFF", "[opcode_table]") {
+    std::string json = R"({ "CMSG_PING": "0x1DC" })";
+    auto path = writeTempJson(json);
+
+    OpcodeTable table;
+    table.loadFromJson(path);
+
+    // SMSG_AUTH_CHALLENGE should not be in this table
+    REQUIRE(table.toWire(LogicalOpcode::SMSG_AUTH_CHALLENGE) == 0xFFFF);
+
+    std::remove(path.c_str());
+}
+
+TEST_CASE("OpcodeTable loadFromJson nonexistent file", "[opcode_table]") {
+    OpcodeTable table;
+    REQUIRE_FALSE(table.loadFromJson("/nonexistent/path/opcodes.json"));
+    REQUIRE(table.size() == 0);
+}
+
+TEST_CASE("OpcodeTable logicalToName returns enum name", "[opcode_table]") {
+    const char* name = OpcodeTable::logicalToName(LogicalOpcode::CMSG_PING);
+    REQUIRE(name != nullptr);
+    REQUIRE(std::string(name) == "CMSG_PING");
+}
+
+TEST_CASE("OpcodeTable decimal wire values", "[opcode_table]") {
+    std::string json = R"({ "CMSG_PING": "476" })";
+    auto path = writeTempJson(json);
+
+    OpcodeTable table;
+    REQUIRE(table.loadFromJson(path));
+    REQUIRE(table.toWire(LogicalOpcode::CMSG_PING) == 476);
+
+    std::remove(path.c_str());
+}
+
+TEST_CASE("Global active opcode table", "[opcode_table]") {
+    OpcodeTable table;
+    std::string json = R"({ "CMSG_PING": "0x1DC" })";
+    auto path = writeTempJson(json);
+    table.loadFromJson(path);
+
+    wowee::game::setActiveOpcodeTable(&table);
+    REQUIRE(wowee::game::getActiveOpcodeTable() == &table);
+    REQUIRE(wowee::game::wireOpcode(LogicalOpcode::CMSG_PING) == 0x1DC);
+
+    // Reset
+    wowee::game::setActiveOpcodeTable(nullptr);
+    REQUIRE(wowee::game::wireOpcode(LogicalOpcode::CMSG_PING) == 0xFFFF);
+
+    std::remove(path.c_str());
+}