Self-hosted z3.sx translator, prove.sx prover, parser unicode, auto reader macros

- z3.sx: SX-to-SMT-LIB translator written in SX (359 lines), replaces Python translation logic
- prove.sx: SMT-LIB satisfiability checker in SX — proves all 91 primitives sat by construction
- Parser: support unicode characters (em-dash, accented letters) in symbols
- Auto-resolve reader macros: #name finds name-translate in component env, no Python registration
- Platform primitives: type-of, symbol-name, keyword-name, sx-parse registered in primitives.py
- Cond heuristic: predicates ending in ? recognized as Clojure-style tests
- Library loading: z3.sx loaded at startup with reload callbacks for hot-reload ordering
- reader_z3.py: rewritten as thin shell delegating to z3.sx
- Split monolithic .sx files: essays (22), plans (13), reactive-islands (6) into separate files

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

shared/sx/evaluator.py

@@ -233,13 +233,20 @@ def _sf_cond(expr: list, env: dict) -> Any:
     clauses = expr[1:]
     if not clauses:
         return NIL
-    # Detect scheme-style: first clause is a 2-element list that isn't a comparison
+    # Detect scheme-style: first clause is a 2-element list that isn't a
+    # comparison or predicate call (predicates end in ?)
+    def _is_clojure_test(clause):
+        if not isinstance(clause, list) or len(clause) != 2:
+            return False
+        head = clause[0]
+        if not isinstance(head, Symbol):
+            return False
+        return (head.name in ("=", "<", ">", "<=", ">=", "!=", "and", "or")
+                or head.name.endswith("?"))
     if (
         isinstance(clauses[0], list)
         and len(clauses[0]) == 2
-        and not (isinstance(clauses[0][0], Symbol) and clauses[0][0].name in (
-            "=", "<", ">", "<=", ">=", "!=", "and", "or",
-        ))
+        and not _is_clojure_test(clauses[0])
     ):
         for clause in clauses:
             if not isinstance(clause, list) or len(clause) < 2: