(fix) print error from Arr[S].WithTaskf (#73)

(fix) optional formatting for done i/o at Arr[S] (#72)

(fix) change the BiMap notation to Codec (#71)

(fea) `Hoist: Arr[T] -> Arr[S]` (#70)

(fix) console output abstraction (#68)

(fix) copy runtime with file system (#67)

allow sub-agent to use own filesystem

(fea) Type-level composition of agents (#66)

* (fea) agents composition algebra (see article)
* (fea) add PDF version of the article
* (fix) prevent auto derivation for Lens[S, S]

(fix) invalid condition on tool selection loop (#65)

(fix) support multiple native functions per server (#64)

(fix) crash on nil registry (#63)