fix(audit): initialize log file when audit logging is enabled

src/security/audit.rs

@@ -166,6 +166,9 @@ impl AuditLogger {
     /// Create a new audit logger
     pub fn new(config: AuditConfig, zeroclaw_dir: PathBuf) -> Result<Self> {
         let log_path = zeroclaw_dir.join(&config.log_path);
+        if config.enabled {
+            initialize_audit_log_file(&log_path)?;
+        }
         Ok(Self {
             log_path,
             config,
@@ -182,6 +185,8 @@ impl AuditLogger {
         // Check log size and rotate if needed
         self.rotate_if_needed()?;
 
+        initialize_audit_log_file(&self.log_path)?;
+
         // Serialize and write
         let line = serde_json::to_string(event)?;
         let mut file = OpenOptions::new()
@@ -258,6 +263,20 @@ impl AuditLogger {
     }
 }
 
+fn initialize_audit_log_file(log_path: &std::path::Path) -> Result<()> {
+    if let Some(parent) = log_path.parent() {
+        if !parent.as_os_str().is_empty() {
+            std::fs::create_dir_all(parent)?;
+        }
+    }
+
+    let _ = OpenOptions::new()
+        .create(true)
+        .append(true)
+        .open(log_path)?;
+    Ok(())
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;
@@ -333,6 +352,39 @@ mod tests {
         Ok(())
     }
 
+    #[test]
+    fn audit_logger_enabled_creates_file_on_init() -> Result<()> {
+        let tmp = TempDir::new()?;
+        let config = AuditConfig {
+            enabled: true,
+            ..Default::default()
+        };
+
+        let _logger = AuditLogger::new(config, tmp.path().to_path_buf())?;
+        assert!(
+            tmp.path().join("audit.log").exists(),
+            "audit log file should be created when audit logging is enabled"
+        );
+        Ok(())
+    }
+
+    #[test]
+    fn audit_logger_enabled_creates_parent_directories() -> Result<()> {
+        let tmp = TempDir::new()?;
+        let config = AuditConfig {
+            enabled: true,
+            log_path: "logs/security/audit.log".to_string(),
+            ..Default::default()
+        };
+
+        let _logger = AuditLogger::new(config, tmp.path().to_path_buf())?;
+        assert!(
+            tmp.path().join("logs/security/audit.log").exists(),
+            "audit logger should create nested directories for configured log path"
+        );
+        Ok(())
+    }
+
     // ── §8.1 Log rotation tests ─────────────────────────────
 
     #[tokio::test]