[BUG] .NET patching hangs without --debug flag

[robert-cronin]

Version of copa

v0.0.13

Expected Behavior

copa patch completes .NET image patching in ~18 seconds (as it does with --debug).

Actual Behavior

copa patch hangs indefinitely after the DLL patching phase completes, eventually timing out. Adding --debug makes the same operation succeed in ~18 seconds.

The root cause is the BuildKit progress channel is unbuffered. .NET patching generates heavy output (dotnet restore, DLL copying, deps.json updates) which causes backpressure against the progrock TUI. --debug uses PlainMode which writes directly to stderr and never blocks.

Steps To Reproduce

No response

Are you willing to submit PRs to contribute to this bug fix?

• Yes, I am willing to implement it.