fix: build_rdm_frame checksum off-by-one (summed 1 extra byte incl. stale template checksum)

Default mode RDM discovery got 0 responses because the template-based builder's
checksum range was 0x3C..0x3C+msgLen (includes the old checksum slot) instead of
0x3C..0x53+PDL. build_rdm_frame2 was already correct (used by show mode).

src/hostdemo.rs

@@ -93,9 +93,10 @@ fn build_rdm_frame(dest: &[u8; 6], tn: u8, qseq: u16, cc: u8, pid: u16, pd: &[u8
     f[0x51] = (pid & 0xFF) as u8;
     f[0x52] = pd.len() as u8;
     f[0x53..0x53 + pd.len()].copy_from_slice(pd);
-    // checksum: 含隐式 0xCC 起始字节, 从 CC 起 msgLen 字节 (不含自身), BE
+    // checksum: 含隐式 0xCC 起始字节, Σ(0x3C..0x53+PDL) (不含 checksum 槽位自身!), BE
+    // ★历史 bug: 曾写成 0x3C..0x3C+msg_len 多算 1 字节(含模板残留旧 checksum) → Butler 不应答
     let mut sum: u16 = 0xCC;
-    for i in 0x3C..0x3C + msg_len { sum = sum.wrapping_add(f[i] as u16); }
+    for i in 0x3C..0x53 + pd.len() { sum = sum.wrapping_add(f[i] as u16); }
     let cs = 0x53 + pd.len();
     f[cs] = (sum >> 8) as u8;
     f[cs + 1] = (sum & 0xFF) as u8;
@@ -1107,6 +1108,14 @@ pub fn run(target: &str, bind_ip: &str, secs: u64) {
                 if src.ip().to_string() == target && n == 47 { reg = true; break; }
             }
         }
+        // CLAIM_BINDFF=1: 认领前先发单个 bind52(ffff), 测试能否解除 Butler 拒答态 (bind 中毒恢复实验)
+        if std::env::var("CLAIM_BINDFF").unwrap_or_default() == "1" {
+            let mut b = build_bind52([0xff, 0xff]);
+            b[0x1A..0x1E].copy_from_slice(&[o2[3], o2[2], o2[1], o2[0]]);
+            sock.send_to(&b, &dst).unwrap();
+            std::thread::sleep(Duration::from_millis(320));
+            println!("CLAIM_BINDFF: 已发 bind52(ffff)");
+        }
         let nonce = rng.next();
         let b12c = rng.next();
         let mut ch = load_template("claim_h112");
@@ -1201,7 +1210,9 @@ pub fn run(target: &str, bind_ip: &str, secs: u64) {
     if mode != "skip2" && mode != "noclaim" {
         // 冷启动广播前奏 (cold2=38s, SymphoLight 实测 2.5min 成功; 10s 短前奏被拒!)
         // ★门控假说: Butler 须收到 ~13+ 轮 discovery/announce 才武装认领应答
-        let pre_secs: u64 = std::env::var("HOSTDEMO_PRE").ok().and_then(|s| s.parse().ok()).unwrap_or(45);
+        // ★2026-09-11 消融证伪: 广播前奏不仅非必需而且有毒 (PRE=45 认领FAIL / PRE=0 PASS)
+        //   → 默认 PRE=0; 复现 SL 行为用 HOSTDEMO_PRE=45
+        let pre_secs: u64 = std::env::var("HOSTDEMO_PRE").ok().and_then(|s| s.parse().ok()).unwrap_or(0);
         // ★宣告帧用 announce_live 模板 + 新鲜时间戳/随机会话 ID (陈旧宣告 = 僵尸主机, 认领被无视)
         let euce = load_template("euce"); // 540B, 无主机相关字段
         let pre = Instant::now();
@@ -1236,21 +1247,21 @@ pub fn run(target: &str, bind_ip: &str, secs: u64) {
                 println!("    [dbg] 前奏期收帧 len={} src={}", n, src);
             }
         }
-        let mut ident = IDENT102.to_vec();
+        // ★bind52×4 实测有毒 (2026-09-11 消融: skip2 认领PASS / 仅加bind×4 即 FAIL) —
-        ident[0x1C..0x20].copy_from_slice(&[o[3], o[2], o[1], o[0]]);
+        // ffff→0000→ffff→0000 以 0000(unbind) 收尾, Butler 进入未绑定态后无视 AECH。
-        // ★sub=07 绑定帧 ×4: ffff→0000→ffff→0000 (间隔 ~0.32s, sym_startup @98.8-99.5 实测)
+        // 默认不再发送; 复现实验用 HOSTDEMO_BIND=1 开启。
-        // 1.8s 后发 ident
+        if std::env::var("HOSTDEMO_BIND").unwrap_or_default() == "1" {
-        for flag in [[0xff_u8, 0xff_u8], [0x00, 0x00], [0xff, 0xff], [0x00, 0x00]] {
+            for flag in [[0xff_u8, 0xff_u8], [0x00, 0x00], [0xff, 0xff], [0x00, 0x00]] {
-            let mut b = build_bind52(flag);
+                let mut b = build_bind52(flag);
-            b[0x1A..0x1E].copy_from_slice(&[o[3], o[2], o[1], o[0]]);
+                b[0x1A..0x1E].copy_from_slice(&[o[3], o[2], o[1], o[0]]);
-            sock.send_to(&b, &dst).unwrap();
+                sock.send_to(&b, &dst).unwrap();
-            std::thread::sleep(Duration::from_millis(320));
+                std::thread::sleep(Duration::from_millis(320));
+            }
+            std::thread::sleep(Duration::from_millis(1800));
         }
-        std::thread::sleep(Duration::from_millis(1800));
+        // IDENT102 常量帧 0x1A 起已是本机 IP+MAC — 不要再补丁 (旧代码 patch 0x1C 会踩坏 MAC 高2字节!)
-        let mut ident = IDENT102.to_vec();
+        sock.send_to(&IDENT102, &dst).unwrap();
-        ident[0x1C..0x20].copy_from_slice(&[o[3], o[2], o[1], o[0]]);
+        println!("[2] 冷启动前奏完成 ({}s 广播 + 身份帧; bind 已默认跳过=有毒)", pre_secs);
-        sock.send_to(&ident, &dst).unwrap();
-        println!("[2] 冷启动前奏完成 ({}s 广播 + 绑定帧×4 + 身份帧)", pre_secs);
     }
     let mut reg_ok = false;
     for _ in 0..10 {
@@ -1269,26 +1280,40 @@ pub fn run(target: &str, bind_ip: &str, secs: u64) {
         }
         for round in 0..3 {
             if mode == "noclaim" { break; }
+        // ★每轮先发身份帧(announce144)等 47B 注册应答, 再发认领 — skip2 实测: 无身份帧直接 claim 被无视
+        let o2a = [o[0], o[1], o[2], o[3]];
+        sock.send_to(&load_template("announce144"), &dst).unwrap();
+        let wr = Instant::now();
+        let mut reg47 = false;
+        while wr.elapsed() < Duration::from_millis(400) {
+            if let Ok((n, _)) = sock.recv_from(&mut buf) {
+                if n == 47 { reg47 = true; break; }
+            }
+        }
         let nonce = rng.next();
-        let mut ch = load_template("claim_h112");
+        let ch = build_claim_frame(o2a, nonce, b12);
-        ch[0x1A..0x1E].copy_from_slice(&[o[3], o[2], o[1], o[0]]);
+        // 排空缓存 (前奏自广播回收), 避免 AERE 到达前读循环耗尽
-        ch[0x88..0x8C].copy_from_slice(&nonce.to_le_bytes());
+        while sock.recv_from(&mut buf).is_ok() {}
-        ch[0x8C..0x90].copy_from_slice(&b12.to_le_bytes());
         sock.send_to(&ch, &dst).unwrap();
-        for _ in 0..10 {
+        let w = Instant::now();
-            if let Ok((n, src)) = sock.recv_from(&mut buf) {
+        let mut rx_n = 0u32;
+        let mut rx_lens: Vec<usize> = Vec::new();
+        while w.elapsed() < Duration::from_millis(700) {
+            if let Ok((n, _)) = sock.recv_from(&mut buf) {
+                rx_n += 1;
+                if rx_lens.len() < 8 { rx_lens.push(n); }
                 let b = &buf[..n];
-                println!("    [dbg] AECH等待中收帧 len={} src={} magic={:?}", n, src, &b[0..4.min(n)]);
                 if n > 0xC4 && b.windows(4).any(|w| w == b"AERE") {
                     let resp = g32(b, 0xC0);
                     let want = agios_g(nonce);
-                    println!("[3] AECH 第{}轮: resp=0x{:08x} G=0x{:08x} {}", round + 1, resp, want,
+                    println!("[3] AECH 第{}轮: reg47={} resp=0x{:08x} G=0x{:08x} {}", round + 1, reg47, resp, want,
                         if resp == want { "★PASS" } else { "FAIL" });
                     if resp == want { claim_ok = true; }
                     break;
                 }
             }
         }
+        if !claim_ok { println!("[3] AECH 第{}轮: reg47={} 无AERE (等700ms内收{}帧 {:?})", round + 1, reg47, rx_n, rx_lens); }
         }
     }
     if !claim_ok { println!("[3] 认领失败 (真机只应答源 123.113 的 AECH), 终止"); return; }