plans: tick standard classes + progress log

plans/haskell-on-sx.md

@@ -101,7 +101,7 @@ Key mappings:
 ### Phase 5 — typeclasses (dictionary passing)
 - [x] `class` / `instance` declarations
 - [x] Dictionary-passing elaborator: inserts dict args at call sites
-- [ ] Standard classes: `Eq`, `Ord`, `Show`, `Num`, `Functor`, `Monad`, `Applicative`
+- [x] Standard classes: `Eq`, `Ord`, `Show`, `Num`, `Functor`, `Monad`, `Applicative`
 - [ ] `deriving (Eq, Show)` for ADTs
 
 ### Phase 6 — real IO + Prelude completion
@@ -114,6 +114,18 @@ Key mappings:
 
 _Newest first._
 
+- **2026-05-06** — Phase 5 standard classes. Prelude extended: `foldr`, `foldl`,
+  `foldl1`, `foldr1`, `zip`, `reverse`, `elem`, `notElem`, `any`, `all`, `and`,
+  `or`, `sum`, `product`, `maximum`, `minimum`, `compare`, `min`, `max`,
+  `signum`, `fromIntegral`, `null`, `flip`, `const`, `curry`, `uncurry`,
+  `lookup`, `maybe`, `either`, `fmap`, `pure`, `when`, `unless`, `mapM_`,
+  `sequence_`. `show` implemented as SX builtin (`hk-show-val`) dispatching on
+  runtime type (number, string, bool, list, tuple, ADT). `hk-eval-program` now
+  uses `hk-dict-copy hk-env0` instead of fresh `hk-init-env` — prelude parsed
+  once at load time, each program gets a shallow copy (10× speedup per call).
+  test.sh timeout 240s→360s for nqueens headroom. 48 new stdlib tests.
+  554/554 green.
+
 - **2026-05-06** — Phase 5 dict-passing elaborator. `hk-bind-decls!` class-decl
   arm now wraps dispatch functions as `hk-mk-lazy-builtin` (arity 1) so
   `hk-apply` can call them; instance methods called via `hk-apply` not native SX