feat: CLI 编码模式 + 批量生成 + text_builder

- 新增 core/src/text_builder.rs — Rust 版文本构造（WiFi/vCard/Email/Phone/SMS）
- CLI 新增 --mode 模式参数（wifi/vcard/email/phone/sms/url/batch）
- CLI 新增 --ssid/--password/--name/--phone/--to 等模式专属参数
- CLI 新增 --batch <file> 批量生成（JSON 数组 / CSV）
- 批量支持自动检测 JSON/CSV 格式并自动编号输出
- 新增 6 个 text_builder 单元测试（80 tests total）

core/src/text_builder.rs

@@ -0,0 +1,97 @@
+//! QR 编码文本构造工具
+//!
+//! 集中管理各模式的文本格式（与 gui 前端 `utils/qrText.ts` 功能一致）
+
+/// 构造 WiFi 连接字符串
+pub fn build_wifi_text(ssid: &str, password: &str, encryption: &str, hidden: bool) -> String {
+    let h = if hidden { "H:true;" } else { "" };
+    format!("WIFI:T:{encryption};S:{ssid};P:{password};{h};")
+}
+
+/// 构造 vCard 字符串
+pub fn build_vcard_text(
+    name: &str,
+    phone: &str,
+    email: &str,
+    company: &str,
+    address: &str,
+) -> String {
+    format!("BEGIN:VCARD\nVERSION:3.0\nFN:{name}\nTEL:{phone}\nEMAIL:{email}\nORG:{company}\nADR:{address}\nEND:VCARD")
+}
+
+/// 构造 mailto 链接
+pub fn build_email_text(to: &str, subject: &str, body: &str) -> String {
+    let subject_enc = urlencoding(subject);
+    let body_enc = urlencoding(body);
+    format!("mailto:{to}?subject={subject_enc}&body={body_enc}")
+}
+
+/// 构造电话链接
+pub fn build_phone_text(number: &str) -> String {
+    format!("tel:{number}")
+}
+
+/// 构造短信链接
+pub fn build_sms_text(number: &str, message: &str) -> String {
+    format!("smsto:{number}:{message}")
+}
+
+/// 简易 URL 编码（仅编码特殊字符）
+fn urlencoding(s: &str) -> String {
+    s.chars()
+        .map(|c| match c {
+            ' ' => "%20".into(),
+            '&' => "%26".into(),
+            '=' => "%3D".into(),
+            '#' => "%23".into(),
+            '%' => "%25".into(),
+            '+' => "%2B".into(),
+            '\n' => "%0A".into(),
+            '\r' => "%0D".into(),
+            _ => c.to_string(),
+        })
+        .collect()
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_build_wifi_text() {
+        let text = build_wifi_text("MyWiFi", "pass123", "WPA", false);
+        assert!(text.contains("WIFI:T:WPA;S:MyWiFi;P:pass123;"));
+    }
+
+    #[test]
+    fn test_build_wifi_hidden() {
+        let text = build_wifi_text("HiddenNet", "secret", "WPA2", true);
+        assert!(text.contains("H:true;"));
+    }
+
+    #[test]
+    fn test_build_vcard_text() {
+        let text = build_vcard_text("张三", "13800138000", "a@b.com", "公司", "北京");
+        assert!(text.contains("BEGIN:VCARD"));
+        assert!(text.contains("FN:张三"));
+        assert!(text.contains("END:VCARD"));
+    }
+
+    #[test]
+    fn test_build_email_text() {
+        let text = build_email_text("a@b.com", "Hello World", "Test body");
+        assert!(text.starts_with("mailto:a@b.com"));
+        assert!(text.contains("Hello%20World"));
+    }
+
+    #[test]
+    fn test_build_phone_text() {
+        assert_eq!(build_phone_text("13800138000"), "tel:13800138000");
+    }
+
+    #[test]
+    fn test_build_sms_text() {
+        let text = build_sms_text("13800138000", "Hi");
+        assert_eq!(text, "smsto:13800138000:Hi");
+    }
+}