feat(webgl): Add 4 new GAL test scenarios for expanded coverage

Expand test coverage from ~19% to ~25% of GAL API with modular scenario files:
- bezier-curves: Tests DrawCurve() with S-curves, waves, hearts, and control points
- arc-segments: Tests DrawArcSegment() with thick arc strokes (PCB trace style)
- segment-chain: Tests DrawSegmentChain() with zigzags, spirals, sharp corners
- group-caching: Tests BeginGroup/EndGroup/DrawGroup for cached geometry

Architecture:
- New scenarios in separate files under scenarios/
- Forward declarations in main gal_test_scenarios.cpp
- CMakeLists.txt updated to compile new scenario modules

Also:
- Remove unused build-wxwidgets-native.sh (using system wxWidgets)

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

scripts/build-wxwidgets-native.sh

@@ -1,62 +0,0 @@
-#!/bin/bash
-#
-# Build wxWidgets for native macOS (not WASM)
-# This is used for the native GAL test harness
-#
-
-set -e
-
-SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
-PROJECT_ROOT="$(cd "$SCRIPT_DIR/.." && pwd)"
-WX_SRC="$PROJECT_ROOT/wxwidgets"
-BUILD_DIR="$PROJECT_ROOT/build-native/wxwidgets"
-INSTALL_DIR="$PROJECT_ROOT/build-native/wxwidgets-install"
-LOG_FILE="$PROJECT_ROOT/tests/logs/wxwidgets-native-build.log"
-
-mkdir -p "$(dirname "$LOG_FILE")"
-
-echo "Building wxWidgets for native macOS..."
-echo "  Source: $WX_SRC"
-echo "  Build:  $BUILD_DIR"
-echo "  Install: $INSTALL_DIR"
-echo "  Log:    $LOG_FILE"
-
-# Create build directory
-mkdir -p "$BUILD_DIR"
-cd "$BUILD_DIR"
-
-# Set up paths for homebrew libraries
-export PKG_CONFIG_PATH="/opt/homebrew/lib/pkgconfig:/opt/homebrew/opt/libpng/lib/pkgconfig:$PKG_CONFIG_PATH"
-export CPPFLAGS="-I/opt/homebrew/include $CPPFLAGS"
-export LDFLAGS="-L/opt/homebrew/lib $LDFLAGS"
-
-# Configure wxWidgets for native macOS with OpenGL support
-echo "Configuring..."
-"$WX_SRC/configure" \
-    --prefix="$INSTALL_DIR" \
-    --disable-shared \
-    --with-opengl \
-    --with-osx_cocoa \
-    --disable-webview \
-    --disable-mediactrl \
-    --with-libpng=sys \
-    --with-libjpeg=sys \
-    --with-libtiff=sys \
-    --with-zlib=sys \
-    >> "$LOG_FILE" 2>&1
-
-# Build
-echo "Building (this may take a while)..."
-make -j$(sysctl -n hw.ncpu 2>/dev/null || echo 4) >> "$LOG_FILE" 2>&1
-
-# Install
-echo "Installing..."
-make install >> "$LOG_FILE" 2>&1
-
-echo ""
-echo "wxWidgets native build complete!"
-echo "wx-config: $INSTALL_DIR/bin/wx-config"
-echo ""
-echo "To use in CMake:"
-echo "  set(wxWidgets_CONFIG_EXECUTABLE $INSTALL_DIR/bin/wx-config)"
-echo "  find_package(wxWidgets REQUIRED COMPONENTS core base gl)"