Use when the user expresses something they want recorded as a finding ("we just learned that…", "remember this finding…", "log that…", "we discovered…"). Writes a new markdown file under knowledge/findings/ with proper YAML frontmatter (date, author, related references). The author is the human, not you. If the user is on an exploration (a non-main git branch in the cairn), the finding records that exploration's name.
