fix: land telegram empty-html fallback hardening (#25096) (thanks @Glucksberg)

CHANGELOG.md

@@ -14,6 +14,7 @@ Docs: https://docs.openclaw.ai
 - Security/Native images: enforce `tools.fs.workspaceOnly` for native prompt image auto-load (including history refs), preventing out-of-workspace sandbox mounts from being implicitly ingested as vision input. This ships in the next npm release. Thanks @tdjackey for reporting.
 - Security/Exec approvals: bind `system.run` command display/approval text to full argv when shell-wrapper inline payloads carry positional argv values, and reject payload-only `rawCommand` mismatches for those wrapper-carrier forms, preventing hidden command execution under misleading approval text. This ships in the next npm release. Thanks @tdjackey for reporting.
 - Telegram/Media fetch: prioritize IPv4 before IPv6 in SSRF pinned DNS address ordering so media downloads still work on hosts with broken IPv6 routing. (#24295, #23975) Thanks @Glucksberg.
+- Telegram/Replies: when markdown formatting renders to empty HTML (for example syntax-only chunks in threaded replies), retry delivery with plain text, and fail loud when both formatted and plain payloads are empty to avoid false delivered states. (#25096, #25091) Thanks @Glucksberg.
 - Sessions/Tool-result guard: avoid generating synthetic `toolResult` entries for assistant turns that ended with `stopReason: "aborted"` or `"error"`, preventing orphaned tool-use IDs from triggering downstream API validation errors. (#25429) Thanks @mikaeldiakhate-cell.
 - Usage accounting: parse Moonshot/Kimi `cached_tokens` fields (including `prompt_tokens_details.cached_tokens`) into normalized cache-read usage metrics. (#25436) Thanks @Elarwei001.
 - Doctor/Sandbox: when sandbox mode is enabled but Docker is unavailable, surface a clear actionable warning (including failure impact and remediation) instead of a mild “skip checks” note. (#25438) Thanks @mcaxtr.

src/telegram/bot/delivery.test.ts

@@ -245,7 +245,7 @@ describe("deliverReplies", () => {
   });
 
   it("falls back to plain text when markdown renders to empty HTML in threaded mode", async () => {
-    const runtime = { error: vi.fn(), log: vi.fn() };
+    const runtime = createRuntime();
     const sendMessage = vi.fn(async (_chatId: string, text: string) => {
       if (text === "") {
         throw new Error("400: Bad Request: message text is empty");
@@ -279,7 +279,7 @@ describe("deliverReplies", () => {
   });
 
   it("throws when formatted and plain fallback text are both empty", async () => {
-    const runtime = { error: vi.fn(), log: vi.fn() };
+    const runtime = createRuntime();
     const sendMessage = vi.fn();
     const bot = { api: { sendMessage } } as unknown as Bot;