feat: try/unwrap payload types, LSP format, macro paste, freestanding runtime

- Type `?`/`!` as Result/Option Ok payload (not always int); fix unwrap C types
- LSP 0.18 document formatting (bux fmt) + VS Code format-on-save
- Macro `:type` generics (Array_New<$t>) and operators-only tt paste
- Ship runtime_freestanding.c + BUX_RUNTIME=freestanding + smokes/examples

tools/smoke_lsp_formatting.sh

@@ -0,0 +1,86 @@
+#!/usr/bin/env bash
+# Smoke: textDocument/formatting re-indents with 4 spaces (same as bux fmt).
+set -euo pipefail
+ROOT="$(cd "$(dirname "$0")/.." && pwd)"
+LSP="$ROOT/tools/bux-lsp"
+TMP=$(mktemp -d)
+trap 'rm -rf "$TMP"' EXIT
+
+if [[ ! -x "$LSP" ]]; then
+  echo "building bux-lsp..."
+  (cd "$ROOT" && make lsp >/dev/null)
+fi
+
+# Intentionally bad indent (2 spaces)
+cat > "$TMP/Main.bux" <<'EOF'
+func Main() -> int {
+  let x: int = 1;
+    if x > 0 {
+  return 0;
+    }
+  return 1;
+}
+EOF
+
+rpc() {
+  local body="$1"
+  local len
+  len=$(printf '%s' "$body" | wc -c)
+  printf 'Content-Length: %s\r\n\r\n%s' "$len" "$body"
+}
+
+CONTENT_JSON=$(python3 -c 'import json,sys; print(json.dumps(open(sys.argv[1]).read()))' "$TMP/Main.bux")
+URI="file://$TMP/Main.bux"
+
+{
+  rpc '{"jsonrpc":"2.0","id":1,"method":"initialize","params":{"capabilities":{},"rootUri":"file://'"$TMP"'"}}'
+  rpc '{"jsonrpc":"2.0","method":"initialized","params":{}}'
+  rpc '{"jsonrpc":"2.0","method":"textDocument/didOpen","params":{"textDocument":{"uri":"'"$URI"'","languageId":"bux","version":1,"text":'"$CONTENT_JSON"'}}}'
+  rpc '{"jsonrpc":"2.0","id":2,"method":"textDocument/formatting","params":{"textDocument":{"uri":"'"$URI"'"},"options":{"tabSize":4,"insertSpaces":true}}}'
+  rpc '{"jsonrpc":"2.0","id":3,"method":"shutdown","params":null}'
+  rpc '{"jsonrpc":"2.0","method":"exit","params":null}'
+} | "$LSP" 2>/dev/null | tr '\r' '\n' > "$TMP/out.txt"
+
+python3 - <<'PY' "$TMP/out.txt"
+import json, sys, re
+raw = open(sys.argv[1]).read()
+
+# Find response id=2 with result TextEdit array
+# Prefer structured parse of JSON objects containing "newText"
+ok = False
+version_ok = "0.18.0" in raw or '"documentFormattingProvider":true' in raw.replace(" ", "")
+if "0.18.0" not in raw and "documentFormattingProvider" not in raw:
+    # initialize result may be nested; still require a formatting response
+    pass
+
+# Extract TextEdit newText via regex / brace walk
+edits = []
+for m in re.finditer(r'"newText"\s*:\s*"((?:[^"\\]|\\.)*)"', raw):
+    edits.append(bytes(m.group(1), "utf-8").decode("unicode_escape"))
+
+if not edits:
+    print("FAIL: no TextEdit newText in formatting response")
+    print(raw[:3000])
+    sys.exit(1)
+
+formatted = edits[0]
+# Expected: 4-space indent after func {
+if "    let x: int = 1;" not in formatted:
+    print("FAIL: expected 4-space indent on let")
+    print(repr(formatted))
+    sys.exit(1)
+if "        if x > 0 {" not in formatted and "    if x > 0 {" not in formatted:
+    # after let at indent 1, if should be at indent 1 (same block) = 4 spaces
+    print("FAIL: unexpected if indent")
+    print(repr(formatted))
+    sys.exit(1)
+# Nested body of if at 8 spaces
+if "        return 0;" not in formatted:
+    print("FAIL: expected 8-space indent on return inside if")
+    print(repr(formatted))
+    sys.exit(1)
+
+print("PASS: LSP formatting smoke (4-space brace indent)")
+if "0.18.0" in raw:
+    print("PASS: serverInfo version 0.18.0")
+PY