Address challenge feedback from Discord (#264)

THIS MESSAGE IS GENERATED BY AN AUTOMATED PROCESS.

## Summary

- Based on sanitized public Discord messages, clarifies the two-pass
workflow in Linux Luminarium’s `piping/tee` challenge.
- `DESCRIPTION.md` now directs learners to save the first pipeline
attempt with `tee`, inspect it, and retry with the discovered
information.
- `challenge/college` now provides the same actionable guidance after an
incorrect attempt.
- `tests_private/test_solve.sh` now verifies the failed first attempt,
wrapped recovery hint, saved discovery output, unpiped-command guard,
and successful retry returning a real flag.

## Validation

- `bash -n` passed for `challenge/college` and
`tests_private/test_solve.sh`.
- `nix develop --command pwnshop test
challenges/linux-luminarium/piping/tee` passed: 1 challenge, 1 testcase.
- A recorded PTY playthrough confirmed the save–inspect–retry discovery
flow; the private regression covers the recovery hint and final flag
omitted from the recording.
- `git diff --check` passed.

## Notes / deferred follow-ups

- A Computing 101 assembly bridge remains deferred because the feedback
did not identify a blocking challenge slug, attempted source, checker
output, or independently confirmed missing concept.
- The Getting Started “levels 9–10” report remains deferred because it
lacks an exact challenge and reproduction, and the active curriculum is
maintained in the separate `welcome-dojo` repository.

Author: zardus

challenges/linux-luminarium/piping/tee/DESCRIPTION.md

@@ -31,3 +31,4 @@ Commands succeeded!
 
 Now, you try it!
 This process' `/challenge/pwn` must be piped into `/challenge/college`, but you'll need to intercept the data to see what `pwn` needs from you!
+Use `tee` to duplicate your first attempt into a file, inspect the saved output, and then retry the pipeline with what you learned.

challenges/linux-luminarium/piping/tee/challenge/college

@@ -12,7 +12,7 @@ read SS < <(tail -n1)
 
 if [ "$SS" != "SUPERSECRET:$(tail -c+20 /flag | head -c4)" ]
 then
-	fold -s <<< "The input to 'college' does not contain the correct secret code! This code should be provided by the 'pwn' command. HINT: use 'tee' to intercept the output of 'pwn' and figure out what the code needs to be."
+	fold -s <<< "The input to 'college' does not contain the correct secret code! This code should be provided by the 'pwn' command. HINT: use 'tee' to save the first attempt to a file, inspect the saved output, and then retry the pipeline with what you learned."
 	exit 2
 fi