* docs: replace changelog with upstream divergence table in README
Problem: fork changes were not documented anywhere user-facing. The
auto-generated CHANGELOG.md tracked upstream releases, not fork
divergence.
Solution: delete CHANGELOG.md and add a collapsed <details> block to
README.md with two tables — cherry-picked PRs (by number, with commit
hashes) and triaged upstream issues (by number, with status and
resolution). This gives users a single place to see what the fork
offers over upstream.
* ci: add daily upstream PR mirror workflow
Problem: new upstream PRs required manual monitoring of
stevearc/oil.nvim to discover.
Solution: add a GitHub Actions workflow that runs daily at 08:00 UTC
and creates issues in the fork for any upstream PRs opened in the last
24 hours. Skips dependabot PRs and deduplicates by title prefix.
Issues are labeled upstream/pr for easy filtering.
