yoda: iced_winit unreachable + deprecation cleanup (45→29 warnings)

- conversion.rs: drop 4 duplicate Interaction arms (Cell/Move/Copy/Help)
  that were already handled higher in the same match — pure dead code
  from a past merge, not a real bug.
- platform_specific/wayland/mod.rs: migrate HasRawDisplayHandle →
  HasDisplayHandle (display_handle().map(|h| h.as_raw())).
- conversion.rs: #[allow(deprecated)] on key_code/winit_key_code — the
  warning suggests Meta but no Meta variant exists in this enum
  (only MetaLeft/MetaRight, which aren't equivalent to Super).
- window.rs: #[allow(deprecated)] on enable_ime/disable_ime with TODO
  to migrate set_ime_* → request_ime_update(ImeRequest::*).
- lib.rs: #[allow(deprecated)] on process_event with TODO to migrate
  try_next → try_recv (futures-channel API change).

Leyoda 2026 – GPLv3

winit/src/window.rs

@@ -325,6 +325,10 @@ where
         }
     }
 
+    // TODO(yoda): migrate to Window::request_ime_update(ImeRequest::*).
+    // Legacy set_ime_* still functional but deprecated; full migration
+    // requires ImeCapabilities + ImeRequestData reshape.
+    #[allow(deprecated)]
     fn enable_ime(
         &mut self,
         cursor: Rectangle,
@@ -355,6 +359,7 @@ where
         }
     }
 
+    #[allow(deprecated)] // see TODO on enable_ime
     fn disable_ime(&mut self) {
         if self.ime_state.is_some() {
             self.raw.set_ime_allowed(false);