fix(fnos): reuse content-addressed core runtime

fnos/cmd/runtime_bootstrap

@@ -18,11 +18,15 @@ fail() {
 [ -d "$WHEEL_ROOT" ] || fail "ImageFind 运行环境初始化失败：安装包缺少核心 wheelhouse。"
 [ -f "$CORE_REQUIREMENTS" ] || fail "ImageFind 运行环境初始化失败：安装包缺少核心依赖锁文件。"
 
-VERSION=$(sed -n '1p' "$VERSION_FILE")
-case "$VERSION" in
+PACKAGE_VERSION=$(sed -n '1p' "$VERSION_FILE")
+case "$PACKAGE_VERSION" in
     ''|*[!0-9.]* ) fail "ImageFind 运行环境初始化失败：版本信息无效。" ;;
 esac
-PACKAGE_ID=$(sed -n '2p' "$VERSION_FILE")
+APP_VERSION=$(sed -n '2p' "$VERSION_FILE")
+case "$APP_VERSION" in
+    ''|*[!0-9.]* ) fail "ImageFind 运行环境初始化失败：应用版本信息无效。" ;;
+esac
+PACKAGE_ID=$(sed -n '3p' "$VERSION_FILE")
 case "$PACKAGE_ID" in
     ''|*[!0-9a-f]* ) fail "ImageFind 运行环境初始化失败：安装包指纹无效。" ;;
 esac
@@ -39,8 +43,9 @@ PYTHON_VERSION=$($SYSTEM_PYTHON -c 'import sys; print(f"{sys.version_info.major}
 [ "$PYTHON_VERSION" = "3.12" ] || fail "ImageFind 需要 Python 3.12，当前为 $PYTHON_VERSION。"
 
 mkdir -p "$RUNTIME_ROOT"
-TARGET="$RUNTIME_ROOT/core-$VERSION"
-STAGE="$RUNTIME_ROOT/.core-$VERSION.tmp.$$"
+RUNTIME_ID=$(printf '%s' "$PACKAGE_ID" | cut -c1-16)
+TARGET="$RUNTIME_ROOT/core-$APP_VERSION-$RUNTIME_ID"
+STAGE="$RUNTIME_ROOT/.core-$APP_VERSION-$RUNTIME_ID.tmp.$$"
 CURRENT="$RUNTIME_ROOT/current"
 
 runtime_valid() {
@@ -51,7 +56,7 @@ runtime_valid() {
         IMAGEFIND_DATA_DIR="$DATA_ROOT/data" "$1/bin/python" -c \
             'import imagefind; print(imagefind.__version__)' 2>"$RUNTIME_ROOT/version-check.err"
     ) || return 1
-    [ "$RUNTIME_VERSION" = "$VERSION" ]
+    [ "$RUNTIME_VERSION" = "$APP_VERSION" ]
 }
 
 if ! runtime_valid "$TARGET"; then
@@ -83,7 +88,7 @@ if ! runtime_valid "$TARGET"; then
             fail "ImageFind 核心运行环境校验失败。"
         }
     if [ -e "$TARGET" ]; then
-        BACKUP="$RUNTIME_ROOT/core-$VERSION.invalid.$(date +%s)"
+        BACKUP="$RUNTIME_ROOT/core-$APP_VERSION-$RUNTIME_ID.invalid.$(date +%s)"
         mv "$TARGET" "$BACKUP"
     fi
     mv "$STAGE" "$TARGET"
@@ -122,5 +127,22 @@ if ! runtime_valid "$CURRENT"; then
     else
         ACTUAL_VERSION='Python 不可执行'
     fi
-    fail "ImageFind 核心运行环境切换失败：期望版本 $VERSION，current=$CURRENT_LINK，实际版本=$ACTUAL_VERSION。"
+    fail "ImageFind 核心运行环境切换失败：期望版本 $APP_VERSION，current=$CURRENT_LINK，实际版本=$ACTUAL_VERSION。"
 fi
+
+# Keep the active runtime plus one most-recent rollback candidate. fnOS package
+# build numbers change on every release, so retaining every historical venv
+# would otherwise grow the application data directory without bound.
+ROLLBACK_KEPT=0
+for OLD_RUNTIME in $(ls -dt "$RUNTIME_ROOT"/core-* 2>/dev/null || true); do
+    [ -d "$OLD_RUNTIME" ] || continue
+    [ "$OLD_RUNTIME" = "$TARGET" ] && continue
+    case "$OLD_RUNTIME" in
+        *.invalid.*) rm -rf -- "$OLD_RUNTIME"; continue ;;
+    esac
+    if [ "$ROLLBACK_KEPT" -eq 0 ]; then
+        ROLLBACK_KEPT=1
+    else
+        rm -rf -- "$OLD_RUNTIME"
+    fi
+done