feat: harden support, localize knowledge and add operator availability [skip ci]

Source-only publication of reviewed commit 64e96a7f423673dc29ad56485be9fc79bce8af1c.

Passed in isolation: focused frontend/backend tests, race checks, TypeScript typecheck, lint, Go compilation, Flowgram build, and deterministic SDK build/tests.

Not accepted as a production release: Next.js export/native assembly remains blocked by environment memory limits; browser interaction and MySQL staging acceptance remain unverified. No production server, database/schema, runtime configuration, deployment, release tag, or workflow execution was performed.

Expected source tree: 0a4a7528e9.

web/components/support-chat/customer-message-editor.tsx

@@ -1,3 +1,5 @@
+// Modified in the independent hardening fork; see docs/hardening/README.md.
+// Modified for AgentDeskFixes: forward customer conversation identity and pending-send state.
 "use client"
 
 import {
@@ -6,6 +8,9 @@ import {
 } from "@/components/chat/shared-message-editor"
 
 type CustomerMessageEditorProps = {
+  conversationId?: number | null
+  draftScope?: string
+  sending?: boolean
   disabled?: boolean
   uploadingAsset?: boolean
   onSend: (html: string) => Promise<void>
@@ -14,6 +19,9 @@ type CustomerMessageEditorProps = {
 }
 
 export function CustomerMessageEditor({
+  conversationId,
+  draftScope,
+  sending = false,
   disabled = false,
   uploadingAsset = false,
   onSend,
@@ -23,6 +31,9 @@ export function CustomerMessageEditor({
   return (
     <SharedMessageEditor
       variant="customer"
+      conversationId={conversationId}
+      draftScope={draftScope}
+      sending={sending}
       disabled={disabled}
       uploadingAsset={uploadingAsset}
       manageLocalUploading