Root cause: compile-and-eval for def created Janet global but never
interned the var in Jolt's namespace. Bare symbols fell through to
interpreter which couldn't find them.
Fixes:
- eval-string: bare symbols and tuples now go through compile path
- compile-and-eval: def/defn/defn- forms intern result in Jolt namespace
- New tests: defn/def integration (4 assertions)
All 317 tests pass.
- throw: emit (error val) in Janet
- try/catch/finally: map to Janet (try body ([err] handler))
- loop*/recur: emit closure-based loop (do (var f nil) (set f (fn [args] body)) (f init-vals))
- recur rewrites to loop function call at emit time
- All 317 tests pass + 5 new Phase 5 tests
- loader.janet: load-ns with compile? dispatch, compiled-cache, compiled?, clear-compiled-cache
- compiler.janet: compile-ast (Janet data structures for direct eval), compile-and-eval
- api.janet: compile-string, compile-file, eval-string dispatches to compile-and-eval when :compile? is true
- types.janet: :compile? flag and :compiled-cache table in context env
- Stateful forms (def, defmacro, ns, deftype, defmulti, defmethod) fall back to interpreter
- All 317 tests pass + 16 new Phase 3 tests
