refactor(flow): remove Live Activity and keep-alive mode picker

Keep voice sessions on silent low-profile PiP only, and fix custom polish style editor presentation via sheet(item:).

README.en.md

@@ -55,7 +55,7 @@ Voice input for iPhone, iPad, and Mac. Speak in any app — polished text lands
 | Post-polish translation | ✅ | ✅ |
 | Personal dictionary | ✅ iCloud sync; protects polish and boosts English suggestions | ✅ |
 | Dictation history | ✅ | ✅ |
-| Live UI | ✅ Dynamic Island | ✅ floating pill |
+| Live UI | — (silent background keep-alive) | ✅ floating pill |
 
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