refactor: optimize string concatenation and add startup statistics

- Replace string concatenation with .formatted() method for better readability
- Add StartupStatistics class to track initialization metrics
- Add detailed startup logging with timing information
  - Scan time
  - IOC time
  - Injection time
  - PostConstruct time
  - Total startup time
- Add banner output support (banner.txt or defBanner.txt)
- Add @Lazy annotation support for lazy initialization

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

src/main/java/com/imyeyu/inject/StartupStatistics.java

@@ -0,0 +1,28 @@
+package com.imyeyu.inject;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * 启动统计信息
+ *
+ * @author 夜雨
+ * @since 2026-01-13 01:29
+ */
+class StartupStatistics {
+
+	final List<String> scannedPackages = new ArrayList<>();
+	int scannedClasses = 0;
+	int registeredBeans = 0;
+	int injectedFields = 0;
+	int postConstructInvocations = 0;
+
+	long scanStartTime = 0;
+	long scanEndTime = 0;
+	long iocStartTime = 0;
+	long iocEndTime = 0;
+	long injectionTotalTime = 0;
+	long injectionCurrentStart = 0;
+	long postConstructTotalTime = 0;
+	long postConstructCurrentStart = 0;
+}