`die` and `stream-file` output silently goes to stdout — blocked on let-go `*out*` semantics

[mparrett]

A few places rely on (binding [*out* …] …) to redirect output, but the rebinding is currently a no-op, so output lands on the wrong stream:

• Error reports go to stdout, not stderr. die (cli.lg:6, imgstore.lg:17, container.lg:26) does (binding [*out* *err*] (println …)), but println ignores the *out* rebinding and writes to stdout.
• Container log streaming goes to lgcr's own stdout. stream-file (container.lg:1060) does (binding [*out* sink] (print chunk)), and it's called with *out*/*err* sinks for stdout.log/stderr.log at container.lg:1344-1345. print ignores the sink binding the same way.

Reproduce on current let-go (no lgcr needed):

$ lg -e '(binding [*out* *err*] (println "x"))'  # "x" -> stdout, stderr empty
$ lg -e '(let [f (open "/tmp/s" :write)] (binding [*out* f] (print "y")) (close! f))'
$ cat /tmp/s                                      # empty — "y" went to stdout, not the file

Root cause is upstream: let-go's top-level print fns (print/pr/prn/println) write straight to os.Stdout and don't consult *out*, so (binding [*out* x] (println …)) has no effect. The lgcr code is written correctly per Clojure semantics — the runtime just doesn't honor it yet. Tracked in nooga/let-go#79, which has a proposed fix and a working implementation.

No lgcr code change is needed: once the let-go fix lands and the pin bumps to a release that includes it, die and stream-file start behaving as written. Add a regression test at that point so a later let-go change can't silently re-break error routing.

Filing mainly as a tracking link from the affected project; will close on the pin bump.

[mparrett]

Draft PR for the upstream fix is up: nooga/let-go#206 — routes print/pr/prn/println through *out* and error sites through *err*, which is what unblocks die/stream-file here. Will close this once a release lands and the pin bumps.

[mparrett]

Update: nooga/let-go#206 merged 2026-06-10 — print/pr/prn/println now route through *out* and error sites through *err*, which is what die/stream-file need here. The fix is on let-go main but not in a release yet; the latest is v1.10.0, which predates the merge. Will close this once the next let-go release ships and lgcr picks it up.