Previous PRs (#150, #179) added partial implementations that left duplicate
code via a rebase conflict: plain (non-linked) text above the stacktrace and a
clickable link section below it. This consolidates both into a single clickable
link above the stacktrace.
Also makes `gitHash` an injectable constructor parameter so tests can exercise
the link without needing a release build.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>