cleanup: remove dead code and duplicate docs

- Remove session-ses_2f27.md (161KB raw session log)
- Remove 49 ROOT_* duplicate files across REFERENCE/
- Remove 14 duplicate files between REFERENCE/ root and history/
- Remove asr_legacy.rs (dead code, replaced by asr.rs)
- Remove src/core/worker/ (duplicate JobWorker)
- Remove src/core/layers/ (empty directory)
- Remove 4 .bak files in src/
- Remove 7 dead private methods in worker/processor.rs
- Remove backup directory from git tracking

src/core/storage/uuid.rs

@@ -54,22 +54,81 @@ pub fn compute_uuid_from_relative_path(relative_path: &str) -> String {
     compute_uuid(&username, &filepath)
 }
 
-/// Get MAC address of primary network interface
+/// 取得本機內建網路介面的 MAC 位址（不可拆、非外接）。
+/// 優先順序：en0 (Wi-Fi) > en1 > 其他非 USB/Thunderbolt 介面。
+/// 若都找不到則回傳 fallback。
 /// Returns MAC address in format: a1:b2:c3:d4:e5:f6
 pub fn get_mac_address() -> String {
-    use mac_address::get_mac_address;
+    // 使用 ifconfig 列出所有介面
+    let output = std::process::Command::new("ifconfig")
+        .args(["-a"])
+        .output()
+        .ok()
+        .and_then(|o| {
+            if o.status.success() {
+                Some(String::from_utf8_lossy(&o.stdout).to_string())
+            } else {
+                None
+            }
+        })
+        .unwrap_or_default();
 
-    match get_mac_address() {
-        Ok(Some(mac)) => {
-            let bytes = mac.bytes();
-            format!(
-                "{:02x}:{:02x}:{:02x}:{:02x}:{:02x}:{:02x}",
-                bytes[0], bytes[1], bytes[2], bytes[3], bytes[4], bytes[5]
-            )
+    // 解析 ifconfig，找到介面名稱與 MAC
+    let mut current_iface = String::new();
+    let mut candidates: Vec<(u32, String)> = Vec::new();
+
+    for line in output.lines() {
+        let trimmed = line.trim();
+        // 介面名稱行，如 "en0: flags=..."
+        if !trimmed.starts_with('\t') && trimmed.contains(": flags=") {
+            current_iface = trimmed.split(':').next().unwrap_or("").to_string();
+        }
+
+        // macOS: "ether a1:b2:c3:d4:e5:f6"
+        if let Some(mac_str) = trimmed.strip_prefix("ether ") {
+            let mac = mac_str.trim();
+            if mac.len() == 17 && mac.chars().filter(|&c| c == ':').count() == 5 {
+                if mac == "00:00:00:00:00:00" || mac == "ff:ff:ff:ff:ff:ff" {
+                    continue;
+                }
+                // 優先級：en0=0, en1=1, en2=2, 其他=100
+                let priority = match current_iface.as_str() {
+                    "en0" => 0,
+                    "en1" => 1,
+                    "en2" => 2,
+                    _ if current_iface.starts_with("en") => 3,
+                    _ => 100,
+                };
+                candidates.push((priority, mac.to_string()));
+            }
+        }
+        // macOS: "lladdr a1:b2:c3:d4:e5:f6"
+        if let Some(mac_str) = trimmed.strip_prefix("lladdr ") {
+            let mac = mac_str.trim();
+            if mac.len() == 17 && mac.chars().filter(|&c| c == ':').count() == 5 {
+                if mac == "00:00:00:00:00:00" || mac == "ff:ff:ff:ff:ff:ff" {
+                    continue;
+                }
+                let priority = match current_iface.as_str() {
+                    "en0" => 0,
+                    "en1" => 1,
+                    "en2" => 2,
+                    _ if current_iface.starts_with("en") => 3,
+                    _ => 100,
+                };
+                candidates.push((priority, mac.to_string()));
+            }
         }
-        Ok(None) => "00:00:00:00:00:00".to_string(),
-        Err(_) => "00:00:00:00:00:00".to_string(),
     }
+
+    // 按優先級排序（en0 > en1 > en2 > 其他）
+    candidates.sort_by_key(|k| k.0);
+    if let Some(mac) = candidates.first().map(|c| c.1.clone()) {
+        return mac;
+    }
+
+    // fallback
+    "00:00:00:00:00:00".to_string()
 }
 
 /// Compute Birth UUID (Stable Identity with Location)