Title screen: licence line and a link to the repository at the bottom

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/platform.rs

@@ -15,6 +15,7 @@ mod imp {
         fn dc_storage_get(key: *const u8, key_len: u32) -> i32;
         fn dc_storage_take(dst: *mut u8);
         fn dc_coarse_pointer() -> i32;
+        fn dc_open_url(u: *const u8, ul: u32);
         fn dc_prompt(t: *const u8, tl: u32, d: *const u8, dl: u32) -> i32;
         fn dc_storage_set(key: *const u8, key_len: u32, val: *const u8, val_len: u32);
         fn dc_cache_set(key: *const u8, key_len: u32, val: *const u8, val_len: u32);
@@ -62,6 +63,10 @@ mod imp {
         unsafe { dc_coarse_pointer() != 0 }
     }
 
+    pub fn open_url(url: &str) {
+        unsafe { dc_open_url(url.as_ptr(), url.len() as u32) }
+    }
+
     // asks for a text with the browser's dialog; None when cancelled
     pub fn prompt(title: &str, default: &str) -> Option<String> {
         unsafe {
@@ -122,6 +127,7 @@ mod imp {
     pub fn coarse_pointer() -> bool {
         false
     }
+    pub fn open_url(_url: &str) {}
     pub fn storage_set(key: &str, val: &str) {
         STORE.with(|s| s.borrow_mut().insert(key.to_string(), val.to_string()));
     }