feat: remove obsolete design documents for clipboard OSC52, diff view, file mention, context compaction, and add development guide

apps/interfaces/tui/src/state.rs

@@ -780,7 +780,7 @@ pub fn resolve_context_window(
             return max as usize;
         }
     }
-    128_000
+    256_000
 }
 
 /// Count tokens using tiktoken, fall back to character estimation.