Add cell debug page.

This makes it much easier to troubleshoot information related to a cell
by showing detailed data about a single cell. At this point much is a
placeholder, but we at least get the cell boundary coordinates and a
map.

This also starts to make some code common around doing things like
mapping.

strings.go

@@ -0,0 +1,34 @@
+package main
+
+import (
+	"strconv"
+	"strings"
+)
+
+func HexToInt64(hexStr string) (int64, error) {
+	// Remove "0x" prefix if present
+	hexStr = strings.TrimPrefix(hexStr, "0x")
+	hexStr = strings.TrimPrefix(hexStr, "0X")
+
+	// Parse hex string to uint64
+	value, err := strconv.ParseInt(hexStr, 16, 64)
+	if err != nil {
+		return 0, err
+	}
+
+	return value, nil
+}
+
+func HexToUint64(hexStr string) (uint64, error) {
+	// Remove "0x" prefix if present
+	hexStr = strings.TrimPrefix(hexStr, "0x")
+	hexStr = strings.TrimPrefix(hexStr, "0X")
+
+	// Parse hex string to uint64
+	value, err := strconv.ParseUint(hexStr, 16, 64)
+	if err != nil {
+		return 0, err
+	}
+
+	return value, nil
+}