Add 8HP layout with fully automated routing pipeline

- Update PCB to 8HP format (40x100mm) with v2 component placement
- Add automated routing scripts (autoroute.py runs full pipeline headlessly)
- Update panel spec and SVG for 8HP dimensions
- Board routes in <1 second with 0 unconnected pads

Scripts:
- autoroute.py: Full CLI pipeline (place → export → route → import → DRC)
- autoroute_full.py: Same pipeline for KiCad scripting console
- place_8hp.py: Component placement only
- route.sh/freeroute.sh: Routing helpers

hardware/kicad/scripts/freeroute.sh

@@ -0,0 +1,46 @@
+#!/bin/bash
+# Freerouting automation script
+# Usage: ./scripts/freeroute.sh
+#
+# Prerequisites: Export DSN from KiCad first (File → Export → Specctra DSN)
+
+set -e
+cd "$(dirname "$0")/.."
+
+DSN_FILE="SN-L00.dsn"
+SES_FILE="SN-L00.ses"
+FREEROUTING_JAR="/tmp/freerouting.jar"
+FREEROUTING_URL="https://github.com/freerouting/freerouting/releases/download/v2.0.1/freerouting-2.0.1.jar"
+
+echo "=================================="
+echo "SN-L00 Freerouting Automation"
+echo "=================================="
+
+# Check DSN exists
+if [ ! -f "$DSN_FILE" ]; then
+    echo "ERROR: $DSN_FILE not found"
+    echo "Export from KiCad: File → Export → Specctra DSN"
+    exit 1
+fi
+
+# Download Freerouting if needed
+if [ ! -f "$FREEROUTING_JAR" ]; then
+    echo "Downloading Freerouting..."
+    curl -L -o "$FREEROUTING_JAR" "$FREEROUTING_URL"
+fi
+
+# Run Freerouting
+echo "Running Freerouting..."
+java -jar "$FREEROUTING_JAR" \
+    -de "$DSN_FILE" \
+    -do "$SES_FILE" \
+    -mp 200 \
+    -mt 1 \
+    -oit
+
+echo ""
+echo "=================================="
+echo "DONE! Import in KiCad:"
+echo "  File → Import → Specctra Session"
+echo "  Select: $SES_FILE"
+echo "=================================="