unlock with PIN (#8977)

* add custom password to unlock settings

* If not set, use admin password; if set, use custom settings password.
* At least 4 characters.
* Set with gui or command line.

Signed-off-by: 21pages <sunboeasy@gmail.com>

* Update cn.rs

---------

Signed-off-by: 21pages <sunboeasy@gmail.com>
Co-authored-by: RustDesk <71636191+rustdesk@users.noreply.github.com>

src/core_main.rs

@@ -316,6 +316,20 @@ pub fn core_main() -> Option<Vec<String>> {
                 }
             }
             return None;
+        } else if args[0] == "--set-unlock-pin" {
+            #[cfg(feature = "flutter")]
+            if args.len() == 2 {
+                if crate::platform::is_installed() && is_root() {
+                    if let Err(err) = crate::ipc::set_unlock_pin(args[1].to_owned(), false) {
+                        println!("{err}");
+                    } else {
+                        println!("Done!");
+                    }
+                } else {
+                    println!("Installation and administrative privileges required!");
+                }
+            }
+            return None;
         } else if args[0] == "--get-id" {
             println!("{}", crate::ipc::get_id());
             return None;