fix(channels): use platform message IDs to prevent duplicate memories

Fixes #430 - Prevents duplicate memories after restart by using platform message IDs instead of random UUIDs.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/agent/loop_.rs

@@ -1263,7 +1263,11 @@ I will now call the tool with this payload:
 
         let (text, calls) = parse_tool_calls(response);
         assert!(text.contains("Sure, creating the file now."));
-        assert_eq!(calls.len(), 0, "Raw JSON without wrappers should not be parsed");
+        assert_eq!(
+            calls.len(),
+            0,
+            "Raw JSON without wrappers should not be parsed"
+        );
     }
 
     #[test]