fix: 18 bugs across interpreter, reader, emitter, and runtime

- cljMinMax now handles float and mixed int/float arguments
- cljType* covers ckSet, ckTransient, ckAgent
- cljConj and cljVec return vectors instead of lists
- rem uses truncated division semantics (matches Clojure)
- range with negative step terminates correctly
- reduce of empty collection with no init errors instead of returning nil
- swap! extra args flatten correctly
- remove duplicate not definition (dead code)
- ratio literals (1/5) parse correctly
- scientific notation uses correct variable (numTok not tok)
- readSet returns proper set value instead of (set [...]) form
- TCP REPL catches specific exceptions instead of bare except
- initBuiltinMacros guards against duplicate registration
- doseq :while clause no longer generates dead code or infinite loop
- emitter resets all global state on each emitProgram call
- pushLeaf fills gaps with internal nodes instead of nil children

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

lib/cljnim_pvec.nim

@@ -77,17 +77,13 @@ proc pushLeaf[T](node: PVecNode[T], index: int, shift: int, val: seq[T]): PVecNo
   # Push a full leaf (seq of up to 32 values) into the tree at position 'index'
   result = copyNode(node)
   if shift == 0:
-    # Should not happen — we always push into internal nodes
     result = newLeafNode[T](val)
   else:
     let childIdx = (index shr shift) and BRANCHING_MASK
-    if childIdx >= result.children.len:
-      # Need to grow children array
-      let oldLen = result.children.len
-      result.children.setLen(childIdx + 1)
-      for i in oldLen..<childIdx:
-        result.children[i] = nil
-    
+    # Grow children array and fill any gaps with empty internal nodes
+    while result.children.len <= childIdx:
+      result.children.add(newInternalNode[T]())
+
     var child = result.children[childIdx]
     if child.isNil:
       if shift == BRANCHING_BITS:
@@ -96,7 +92,7 @@ proc pushLeaf[T](node: PVecNode[T], index: int, shift: int, val: seq[T]): PVecNo
         child = pushLeaf(newInternalNode[T](), index, shift - BRANCHING_BITS, val)
     else:
       child = pushLeaf(child, index, shift - BRANCHING_BITS, val)
-    
+
     result.children[childIdx] = child
 
 proc pvecConj*[T](v: PersistentVector[T], val: T): PersistentVector[T] =