docs: bug-report instruction offers WIKI_TRACE=1 for a reproduction (#157)

Files changed:
- CHANGES.md
- VERSION
- instructions/bug-report.md

instructions/bug-report.md

@@ -122,6 +122,9 @@ Facts only: no page content, no guessed cause, no advice.
 ## Decision points
 
 - **The user declines the trace?** Run with `--no-trace`. The manifest records the exclusion.
+- **The failure can be reproduced, and there is no trace?** A distributed instance records none by
+  default. Offer to repeat the failing step in one new shell with `WIKI_TRACE=1` set for that
+  session only, then collect. Do not change the checkout's telemetry configuration for it.
 - **The user wants the report to name pages?** Run with `--titles`; the bundle then also carries
   `tree-paths.txt`, which lists every path under `kb/` and `raw/`.
 - **The collector exits 1?** It could not write the bundle (a missing input file, a full disk). Read