feat: lifetime elision, tooling CI, registry, and LSP locals

Ship the QUALITY_PLAN stretch from ownership through ecosystem: C.1
lifetime elision (bootstrap + selfhost), bux fmt/test/doc CI hooks,
stdlib goldens, package registry (bux search/add), and LSP 0.4
position-sensitive locals with inferred let types. Full-tree format
pass plus Map/Set remove double-free fix.

tools/smoke_registry.sh

@@ -0,0 +1,64 @@
+#!/usr/bin/env bash
+# Smoke: registry search + add + install + build with greet package (E.1)
+set -euo pipefail
+ROOT="$(cd "$(dirname "$0")/.." && pwd)"
+BUXC="$ROOT/buxc"
+export BUX_REGISTRY="$ROOT/config/registry.toml"
+
+if [[ ! -x "$BUXC" ]]; then
+  (cd "$ROOT" && make build >/dev/null)
+fi
+
+TMP=$(mktemp -d)
+trap 'rm -rf "$TMP"' EXIT
+
+echo "=== bux search greet ==="
+"$BUXC" search greet | tee "$TMP/search.out"
+grep -q greet "$TMP/search.out"
+
+echo "=== create consumer project ==="
+mkdir -p "$TMP/app/src"
+cat > "$TMP/app/bux.toml" <<'EOF'
+[Package]
+Name    = "registry_consumer"
+Version = "0.1.0"
+Type    = "bin"
+
+[Build]
+Output = "Bin"
+EOF
+
+cat > "$TMP/app/src/Main.bux" <<'EOF'
+import Std::Io::{PrintLine};
+import Std::String::{String_Eq};
+import Std::Test::{Test_AssertTrue, Test_Pass};
+
+func Main() -> int {
+    let msg: String = Greet_Hello("Bux");
+    Test_AssertTrue(String_Eq(msg, "Hello, Bux!"));
+    Test_AssertTrue(String_Eq(Greet_Version(), "0.1.1"));
+    PrintLine(msg);
+    Test_Pass("registry_consumer");
+    return 0;
+}
+EOF
+
+cd "$TMP/app"
+export BUX_STDLIB="$ROOT/lib"
+
+echo "=== bux add greet ==="
+"$BUXC" add greet
+grep -q greet bux.toml
+cat bux.toml
+
+echo "=== bux install ==="
+"$BUXC" install
+test -f bux.lock
+grep -q greet bux.lock
+cat bux.lock
+
+echo "=== bux run ==="
+"$BUXC" run . | tee "$TMP/run.out"
+grep -q "Hello, Bux!" "$TMP/run.out"
+
+echo "PASS: registry smoke (search + add + install + build)"