fix(compiler): retain enum prefixes for containment

new_changelogs/20261029T124500Z-fixed-enum-containment-prefix.md

@@ -0,0 +1,3 @@
+- **Qualified enum members now retain their lexical prefix.** `hide Color`
+  blocks `Color.Red`, while `seal except Color` permits it; containment no
+  longer checks the generated `Color_Red` constant name.

tests/integration/enum_containment/test_enum_containment.sh

@@ -0,0 +1,71 @@
+#!/bin/sh
+# Qualified enum members retain their written prefix through enum lowering so
+# lexical hide/seal checks see the same name the source used.
+set -eu
+
+SCRIPT_DIR="$(CDPATH= cd -- "$(dirname -- "$0")" && pwd)"
+ROOT="$(cd "$SCRIPT_DIR/../../.." && pwd)"
+AE="$ROOT/build/ae"
+[ -x "$AE" ] || { echo "  [SKIP] enum_containment: $AE not built"; exit 0; }
+
+TMPDIR="$(mktemp -d)"
+trap 'rm -rf "$TMPDIR"' EXIT
+
+cat >"$TMPDIR/hide.ae" <<'AE'
+enum Color { Red, Blue }
+main() {
+    {
+        hide Color
+        c = Color.Red
+    }
+}
+AE
+
+cat >"$TMPDIR/seal.ae" <<'AE'
+enum Color { Red, Blue }
+main() {
+    keep = 1
+    {
+        seal except keep
+        c = Color.Red
+    }
+}
+AE
+
+cat >"$TMPDIR/allowed.ae" <<'AE'
+enum Color { Red, Blue }
+main() {
+    {
+        seal except Color
+        c = Color.Red
+    }
+}
+AE
+
+failed=0
+reject() {
+    name="$1"
+    if "$AE" build "$TMPDIR/$name.ae" -o "$TMPDIR/$name" >"$TMPDIR/$name.log" 2>&1; then
+        echo "  [FAIL] enum_containment: $name accepted a blocked enum prefix"
+        failed=1
+        return
+    fi
+    if ! grep -q "'Color' is hidden in this scope" "$TMPDIR/$name.log"; then
+        echo "  [FAIL] enum_containment: $name failed without the containment diagnostic"
+        sed 's/^/    /' "$TMPDIR/$name.log" | head -10
+        failed=1
+    fi
+}
+
+reject hide
+reject seal
+
+if ! "$AE" build "$TMPDIR/allowed.ae" -o "$TMPDIR/allowed" >"$TMPDIR/allowed.log" 2>&1; then
+    echo "  [FAIL] enum_containment: whitelisted enum prefix was rejected"
+    sed 's/^/    /' "$TMPDIR/allowed.log" | head -10
+    failed=1
+fi
+
+[ "$failed" -eq 0 ] || exit 1
+
+echo "  [PASS] enum_containment: hidden and sealed prefixes reject; whitelist accepts"