BUG: DrRacket REPL corrupted (#%top-interaction: bad syntax) after error in definitions area

If a #lang rhombus file fails to compile (e.g., due to an unbound identifier), the DrRacket REPL enters a broken state. Any subsequent expression typed into the REPL fails with #%top-interaction: bad syntax.

Note: This only happens after an error in the definitions area, not from errors raised within the REPL itself.

Current Workaround: Running a file that compiles successfully resets and fixes the DrRacket REPL.

Steps to Reproduce

Make a file with the following code (deliberately having error) and run it in DrRacket:

#lang rhombus
 x

As expected REPL shows error when file is run. But after that, trying to run any valid code in DrRacket REPL also fails with syntax error:

x: unbound identifier in: x            
$ def a = 0      
. #%top-interaction: bad syntax in: (#%top-interaction . def)

Start with the provided #lang rhombus reproducer in DrRacket, comparing the REPL state after a definitions-area compile error with the state after a REPL error. Trace the transition that causes subsequent valid expressions to produce #%top-interaction: bad syntax; done means the REPL accepts those expressions without requiring a successfully compiled file first.