Hashing

hash = lowercase hex sha256( utf8( strip-whitespace( content ) ) )

• strip-whitespace removes every code point with the Unicode White_Space property, including newlines. Formatters (Prettier, gofmt, indentation churn) therefore never invalidate a hash; only token changes do.
• content is the anchored code: the symbol's full declaration span, the region between (excluding) its marker lines, or the whole file.
• References store the first 8 hex characters. Longer prefixes are accepted when comparing. A collision does not corrupt anything; at worst it delays one review prompt.

Known accepted blind spot: a change that alters only whitespace, such as moving a Python statement into or out of a block by indentation alone, hashes identically and will not trigger review. The cost is a missed prompt, not a wrong build, and the formatter resilience is worth more.