bisync: default to fail-closed safety flags

New Bisync jobs and scheduled RC bodies start with checkAccess,
deltaList, recover, resilient, slowHashSyncOnly, conflictResolve=none,
maxDelete=50, and checksum compare. Explicit outer values still win.

lib/rclone/constants.ts

@@ -1,3 +1,22 @@
+// Fail-closed bisync RC defaults (forked rclone). Explicit outer values override.
+export const BISYNC_SAFETY_DEFAULTS = {
+    checkAccess: true,
+    deltaList: true,
+    recover: true,
+    resilient: true,
+    slowHashSyncOnly: true,
+    conflictResolve: 'none',
+    maxDelete: 50,
+    compare: 'size,modtime,checksum',
+} as const
+
+export const BISYNC_SAFETY_SWITCH_DEFAULTS: Record<string, boolean> = {
+    checkAccess: true,
+    deltaList: true,
+    recover: true,
+    resilient: true,
+}
+
 export const RCLONE_CONFIG_DEFAULTS = {
     copy: {
         'multi_thread_cutoff': '64M',

lib/rclone/requests.ts

@@ -1,4 +1,5 @@
 import type { FlagValue } from '../../types/rclone'
+import { BISYNC_SAFETY_DEFAULTS } from './constants'
 import { getFsInfo } from '../format'
 
 // Pure serialization of operation args into ready-to-POST rclone RC requests. This is the
@@ -492,7 +493,10 @@ export function buildBisyncRequests(args: BisyncArgs): RcRequest[] {
     const { fullDirPath: srcFullDirPath, remoteName: srcRemoteName } = getFsInfo(source)
     const { fullDirPath: dstFullDirPath, remoteName: dstRemoteName } = getFsInfo(destination)
 
-    const outer = { ...(options.outer || {}) }
+    const outer: Record<string, FlagValue> = {
+        ...BISYNC_SAFETY_DEFAULTS,
+        ...(options.outer || {}),
+    }
     // Forked rclone: --delta-list refuses to run without --check-access unless --force.
     if (outer.deltaList && !outer.force) {
         outer.checkAccess = true