feat(pages): configurable limits, multi-format packages, and dual versioning

Make Pages package size and history retention system-configurable, support
zip/tar.gz/tar.xz/tar.bz2/tar/7z uploads, prune history with clear keep-N
semantics, and rebind agent config to the live active Pages deployment so
main-config rollback never depends on pruned packages.

pkg/pagesarchive/limits.go

@@ -0,0 +1,38 @@
+// Copyright 2026 Arctel.net
+// SPDX-License-Identifier: Apache-2.0
+
+package pagesarchive
+
+const (
+	defaultMaxFiles      = 1000
+	defaultMaxFileBytes  = 100 * 1024 * 1024
+	defaultMaxTotalBytes = 100 * 1024 * 1024
+	dirPerm              = 0o750
+	filePerm             = 0o644
+)
+
+// normalizeLimits applies defaults for control-plane inspection.
+// Callers that already validated the package should use EnforceLimits=false instead.
+func normalizeLimits(limits Limits) Limits {
+	if limits.MaxFiles <= 0 {
+		limits.MaxFiles = defaultMaxFiles
+	}
+	if limits.MaxFileBytes <= 0 {
+		limits.MaxFileBytes = defaultMaxFileBytes
+	}
+	if limits.MaxTotalBytes <= 0 {
+		limits.MaxTotalBytes = defaultMaxTotalBytes
+	}
+	return limits
+}
+
+func exceedsFileByteLimit(size uint64, maxBytes int64) bool {
+	// maxBytes <= 0 means unlimited (trusted extract path).
+	if maxBytes <= 0 {
+		return false
+	}
+	if size == 0 {
+		return false
+	}
+	return size > uint64(maxBytes) //nolint:gosec // maxBytes is positive
+}