Complete Phase 1: Build KiCad with optional dependencies disabled

Add CMake override modules, stub implementations, and patches to build
KiCad without CURL, libgit2, OpenCASCADE, and ngspice dependencies.

- cmake/: Find modules that provide stub targets when deps disabled
- stubs/include/: Header stubs for curl, git2, ngspice, OCC
- stubs/src/: Implementation stubs for disabled features
- patches/: Consolidated patch for KiCad source modifications
- scripts/: Build helper scripts

Verified full native build on macOS with all optional deps disabled.

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

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

scripts/update-kicad.sh

@@ -0,0 +1,137 @@
+#!/bin/bash
+#
+# KiCad Wasm Port - Update KiCad Submodule
+#
+# This script updates the KiCad submodule to a new version and
+# helps regenerate patches if needed.
+#
+
+set -e
+
+SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+PROJECT_ROOT="$(dirname "$SCRIPT_DIR")"
+KICAD_DIR="$PROJECT_ROOT/kicad"
+PATCHES_DIR="$PROJECT_ROOT/patches"
+
+echo "=== KiCad Wasm Port - Update KiCad ==="
+echo ""
+
+# Check if kicad submodule exists
+if [ ! -d "$KICAD_DIR/.git" ] && [ ! -f "$KICAD_DIR/.git" ]; then
+    echo "Error: KiCad submodule not initialized."
+    echo "Run: git submodule update --init --recursive"
+    exit 1
+fi
+
+# Parse arguments
+TARGET_REF="${1:-}"
+FORCE_UPDATE=0
+
+if [ "$1" = "--force" ] || [ "$2" = "--force" ]; then
+    FORCE_UPDATE=1
+fi
+
+show_usage() {
+    echo "Usage: $0 [<ref>] [--force]"
+    echo ""
+    echo "Arguments:"
+    echo "  <ref>     Git reference (branch, tag, or commit) to update to"
+    echo "            Examples: 8.0, master, v8.0.0, abc1234"
+    echo "  --force   Force update even if patches need manual intervention"
+    echo ""
+    echo "If no ref is provided, shows current KiCad version."
+}
+
+# Show current version
+show_current_version() {
+    cd "$KICAD_DIR"
+    echo "Current KiCad version:"
+    echo "  Branch: $(git rev-parse --abbrev-ref HEAD 2>/dev/null || echo 'detached')"
+    echo "  Commit: $(git rev-parse --short HEAD)"
+    echo "  Date:   $(git log -1 --format=%ci)"
+
+    # Check if there are local modifications
+    if ! git diff --quiet; then
+        echo ""
+        echo "Warning: There are uncommitted changes in the KiCad directory"
+        git status --short
+    fi
+}
+
+# Revert patches before update
+revert_patches() {
+    echo "Reverting existing patches..."
+    cd "$KICAD_DIR"
+
+    for patch_file in "$PATCHES_DIR"/*.patch; do
+        if [ -f "$patch_file" ]; then
+            patch_name="$(basename "$patch_file")"
+            # Try to reverse the patch
+            if git apply --reverse --check "$patch_file" 2>/dev/null; then
+                echo "  Reverting: $patch_name"
+                git apply --reverse "$patch_file"
+            else
+                echo "  Skipping (not applied): $patch_name"
+            fi
+        fi
+    done
+}
+
+# Update submodule
+update_submodule() {
+    local ref="$1"
+    echo ""
+    echo "Updating KiCad to: $ref"
+
+    cd "$KICAD_DIR"
+
+    # Fetch latest
+    echo "Fetching from origin..."
+    git fetch origin
+
+    # Checkout the target ref
+    echo "Checking out $ref..."
+    git checkout "$ref"
+
+    # If it's a branch, pull latest
+    if git rev-parse --verify "origin/$ref" >/dev/null 2>&1; then
+        echo "Pulling latest from origin/$ref..."
+        git pull origin "$ref"
+    fi
+
+    echo ""
+    show_current_version
+}
+
+# Main logic
+if [ -z "$TARGET_REF" ] || [ "$TARGET_REF" = "--force" ]; then
+    show_current_version
+    echo ""
+    show_usage
+    exit 0
+fi
+
+echo "Preparing to update KiCad..."
+echo ""
+
+# Show current version
+show_current_version
+echo ""
+
+# Revert patches first
+revert_patches
+echo ""
+
+# Update submodule
+update_submodule "$TARGET_REF"
+echo ""
+
+# Re-apply patches
+echo "Re-applying patches..."
+"$SCRIPT_DIR/prepare.sh"
+
+echo ""
+echo "=== Update Complete ==="
+echo ""
+echo "Don't forget to test the build:"
+echo "  cd build && cmake --build . --clean-first"