refactor: ZXing对齐 — 容差50pct + 几何验证 + end-based中心 + 废弃代码清理

- detect.rs: 容差从40%提升到50% (对齐ZXing的moduleSize/2)
- detect.rs: 中心点改用ZXing end-based公式 (浮点精度, end - r4 - r3 - r2/2)
- detect.rs: 新增validate_finder_geometry()几何验证
  module_size一致性<10% + 勾股定理偏差<15%
- detect.rs: compute_finder_deviation改用base=total/7
- detect.rs: 删除废弃的estimate_finder_size函数
- perspective.rs: count_finder_hits容差对齐 (base=total/7 + 50pct)
- web/main.rs + cli/main.rs: 修复Rust 1.96新版clippy规则

web/src/main.rs

@@ -69,7 +69,7 @@ fn generate_qr_inner(text: &str, level_str: &str, margin: u8, size: u8, fmt: &st
     if margin > 20 {
         return (StatusCode::BAD_REQUEST, "边距过大（最大 20）").into_response();
     }
-    if size < 1 || size > 20 {
+    if !(1..=20).contains(&size) {
         return (StatusCode::BAD_REQUEST, "模块大小需在 1-20 之间").into_response();
     }
 
@@ -77,7 +77,6 @@ fn generate_qr_inner(text: &str, level_str: &str, margin: u8, size: u8, fmt: &st
         level,
         version: VersionMode::Auto,
         margin,
-        ..Default::default()
     };
 
     let qr = match QrCode::encode(text, config) {