* fix: remove dead libc.blukat.me link from format-string skill
The libc.blukat.me service returns a persistent 502 Bad Gateway,
failing the lychee link-checker CI. libc.rip (listed alongside it)
is the actively maintained equivalent and already covers this
reference.
Claude-Session: https://claude.ai/code/session_016GzpC3TfGGBPLCru2JU32T
* fix: make CODE_OF_CONDUCT.md first line a heading (MD041)
The single-line code of conduct failed markdownlint MD041, which
requires the first line to be a top-level heading. Making the line
itself an h1 keeps it a single line and turns the CI green.
Claude-Session: https://claude.ai/code/session_016GzpC3TfGGBPLCru2JU32T
* Add Contributor Covenant Code of Conduct v2.1
Signal a welcoming contributor environment and bring the community
health score toward 100%.
* Use private reporting channel for CoC enforcement
Point enforcement contact to GitHub Security Advisories instead of the
public issue tracker so that CoC violations can be reported privately.