Fix macOS asset extraction auto-build and docs

- extract_assets.sh: detect Homebrew and pass CMAKE_PREFIX_PATH,
  OPENSSL_ROOT_DIR, and PKG_CONFIG_PATH when auto-building on macOS
  (bare cmake couldn't find Homebrew deps)
- README.md: fix macOS brew command that had comments after line
  continuations (breaks shell execution)
- BUILD_INSTRUCTIONS.md: expand macOS asset extraction section with
  auto-build note and expansion targets

BUILD_INSTRUCTIONS.md

@@ -95,10 +95,15 @@ cmake --build build -j"$(sysctl -n hw.logicalcpu)"
 
 ### Asset Extraction (macOS)
 
+The script will auto-build `asset_extract` if needed (requires `stormlib`).
+It automatically detects Homebrew and passes the correct paths to CMake.
+
 ```bash
 ./extract_assets.sh /path/to/WoW/Data wotlk
 ```
 
+Supports `classic`, `tbc`, `wotlk` targets (auto-detected if omitted).
+
 ---
 
 ## 🪟 Windows (MSYS2 — Recommended)

README.md

@@ -88,8 +88,10 @@ sudo pacman -S sdl2 glm openssl \
 # macOS (Homebrew)
 brew install cmake pkg-config sdl2 glew glm openssl@3 zlib ffmpeg \
              vulkan-loader vulkan-headers shaderc \
-             unicorn \                    # optional: Warden module execution
-             stormlib                     # optional: asset_extract tool
+             unicorn \
+             stormlib
+# unicorn is optional (Warden module execution)
+# stormlib is optional (asset_extract tool)
 ```
 
 ### Container build

extract_assets.sh

@@ -81,7 +81,18 @@ if [ ! -f "$BINARY" ]; then
 
     echo "Building asset_extract..."
     if [ ! -d "$BUILD_DIR" ]; then
-        cmake -S "$SCRIPT_DIR" -B "$BUILD_DIR" -DCMAKE_BUILD_TYPE=Release
+        CMAKE_EXTRA_ARGS=()
+        # On macOS, Homebrew installs to a non-default prefix that CMake
+        # can't find automatically — pass it explicitly.
+        if command -v brew &>/dev/null; then
+            BREW="$(brew --prefix)"
+            CMAKE_EXTRA_ARGS+=(
+                "-DCMAKE_PREFIX_PATH=$BREW"
+                "-DOPENSSL_ROOT_DIR=$(brew --prefix openssl@3)"
+            )
+            export PKG_CONFIG_PATH="$BREW/lib/pkgconfig:$(brew --prefix ffmpeg)/lib/pkgconfig:$(brew --prefix openssl@3)/lib/pkgconfig:$(brew --prefix vulkan-loader 2>/dev/null)/lib/pkgconfig:$(brew --prefix shaderc 2>/dev/null)/lib/pkgconfig${PKG_CONFIG_PATH:+:$PKG_CONFIG_PATH}"
+        fi
+        cmake -S "$SCRIPT_DIR" -B "$BUILD_DIR" -DCMAKE_BUILD_TYPE=Release "${CMAKE_EXTRA_ARGS[@]}"
     fi
     NPROC=$(nproc 2>/dev/null || sysctl -n hw.logicalcpu 2>/dev/null || echo 4)
     cmake --build "$BUILD_DIR" --target asset_extract -- -j"$NPROC"