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_freestanding.sh

@@ -0,0 +1,66 @@
+#!/usr/bin/env bash
+# Smoke: freestanding runtime compiles under -ffreestanding; optional package build.
+set -euo pipefail
+ROOT="$(cd "$(dirname "$0")/.." && pwd)"
+RT="$ROOT/rt/runtime_freestanding.c"
+TMP=$(mktemp -d)
+trap 'rm -rf "$TMP"' EXIT
+
+if [[ ! -f "$RT" ]]; then
+  echo "FAIL: missing $RT"
+  exit 1
+fi
+
+CC="${BUX_CC:-cc}"
+
+echo "=== freestanding: -ffreestanding -c runtime ==="
+"$CC" -ffreestanding -std=c11 -Wall -Wextra -c "$RT" -o "$TMP/rt_fs.o"
+echo "PASS: runtime_freestanding.o"
+
+echo "=== freestanding: BUX_RUNTIME=freestanding build hello-ish ==="
+mkdir -p "$TMP/pkg/src"
+cat > "$TMP/pkg/bux.toml" <<'EOF'
+[Package]
+Name = "fs_smoke"
+Version = "0.1.0"
+EOF
+cat > "$TMP/pkg/src/Main.bux" <<'EOF'
+func Main() -> int {
+    return 42;
+}
+EOF
+
+if [[ ! -x "$ROOT/buxc" ]]; then
+  echo "building buxc..."
+  (cd "$ROOT" && make build >/dev/null)
+fi
+
+# Hosted link still uses libc for crt0; runtime body is freestanding.
+BUX_RUNTIME=freestanding "$ROOT/buxc" build "$TMP/pkg" --release >/dev/null
+OUT="$TMP/pkg/build/fs_smoke"
+if [[ ! -x "$OUT" ]]; then
+  echo "FAIL: binary not produced"
+  exit 1
+fi
+CODE=$("$OUT"; echo $?)
+if [[ "$CODE" != "42" ]]; then
+  echo "FAIL: expected exit 42, got $CODE"
+  exit 1
+fi
+echo "PASS: freestanding runtime package exit 42"
+
+# Optional: object-level nostdlib link experiment (may need extra crt — soft)
+echo "=== freestanding: optional -ffreestanding object of Main.c ==="
+# Generate C then compile Main only with freestanding flags
+BUX_RUNTIME=freestanding "$ROOT/buxc" build "$TMP/pkg" --release >/dev/null
+if [[ -f "$TMP/pkg/build/main.c" ]]; then
+  if "$CC" -ffreestanding -std=c11 -c "$TMP/pkg/build/main.c" -o "$TMP/main_fs.o" 2>"$TMP/main_fs.err"; then
+    echo "PASS: main.c compiles under -ffreestanding"
+  else
+    # Hosted headers in generated C may pull stdint — not a hard fail
+    echo "SKIP: main.c -ffreestanding (generated C may need hosted headers)"
+    head -5 "$TMP/main_fs.err" || true
+  fi
+fi
+
+echo "PASS: freestanding smoke"