Paths, .field, hoisting, and (std hashset)

- (.field value), and get, try-get, set and update for reading and copying
  along a path of fields and keys, with ref-set in the generic operations.
- please-hoist-i-promise-i-am-not-naughty, in the macros section.
- (std set) is (std hashset), and the collector is hash-setting.

🤖 Generated with [ECA](https://eca.dev) (anthropic/claude-opus-4-5)

Co-Authored-By: eca-agent <git@eca.dev>

_04.Appendices.sz

@@ -288,7 +288,7 @@ Every compiled program links against a small set of optimized runtime assemblies
 | @code{Collections} | Persistent @code{(Vec %a)} based on Relaxed Radix Balanced (RRB) trees |
 | @code{SchemeList} | Persistent singly-linked @code{(List %a)} with @code{Cons} and @code{Nil} |
 | @code{Map} | Persistent @code{(Map %k %v)} based on Compressed Hash-Array Mapped Prefix-trees (CHAMP) |
-| @code{BjoSet} | Persistent hash set @code{(Set %a)} |
+| @code{BjoSet} | Persistent hash set @code{(HashSet %a)} |
 | @code{BjoOrderedMap} | Balanced ordered map @code{(OrderedMap %k %v)} |
 | @code{BjoOrderedSet} | Balanced ordered set @code{(OrderedSet %a)} |
 | @code{Bjoml} | Concurrency runtime: lightweight fibers, channels, promises, and CML scheduler |