fix: keep the taker message deliverable when MarkdownV2 parsing fails

[ToRyVand]

Summary

Closes #882.

When a translation contains an unescaped MarkdownV2 reserved character, Telegram rejects the you_took_someone_order send. Because beginTakeSellMessage sends the order's Continue/Cancel buttons right after, the throw was caught by the outer handler and the buttons were never sent — so the taker was left not only without the confirmation text, but without any way to advance or cancel the order until it expired. That's the part worth highlighting: the impact is a stuck trade, not just a missing message.

Approach

The send now goes through a small helper that retries once without parse_mode when Telegram returns 400 can't parse entities, so the flow continues and the buttons are delivered.

• Narrowed to parse errors. Any other failure (429, 403, network) is re-thrown untouched — retrying those could duplicate a message that was already delivered, ignore retry_after, or repeat a call guaranteed to fail. This follows the existing error instanceof TelegramError && error.response.error_code === … pattern in this file.
• Escapes stripped on the retry. The locales carry \. / \( escapes that are meaningless without parse_mode; sending verbatim would show stray backslashes in the funds-risk warning.
• The failing locale is logged, so the offending translation can be corrected at the source.

This complements #872 (escaping the Farsi locale) rather than replacing it: escaping fixes the known characters, this keeps the flow usable if a new one slips through.

Note (not addressed here)

onGoingTakeSellMessage has the same shape — a MarkdownV2 send sitting before the seller's "your order was taken" notification. It's latent today (/fiatsent is safe in all ten locales), so I left it out to keep this scoped to the reported bug. Happy to apply the same helper there if you'd prefer.

Local validation

npx tsc            ✅
npm run lint       ✅
npm run format     ✅
npm test           ✅ 217 passing

Tests cover the plain-text retry, that the action buttons are still delivered, that non-formatting errors are not retried, and that MarkdownV2 is preserved when the locale is safe. Verified the regression test fails without the fix (only 1 send happens; the buttons never go out).

Summary by CodeRabbit

• Bug Fixes

  • Improved message delivery when Markdown formatting errors occur.
  • Automatically retries affected messages as plain text, allowing follow-up action buttons to remain available.
  • Non-formatting errors continue to be handled normally.

• Tests

  • Added coverage for formatting failures, non-formatting errors, and locales where Markdown formatting succeeds.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Repository UI

Review profile: CHILL

Plan: Pro Plus

Run ID: ffcb858b-c040-4ed7-8e0a-acdaf492209f

📥 Commits

Reviewing files that changed from the base of the PR and between 1ff500b and d16d6e8.

📒 Files selected for processing (2)

• bot/messages.ts
• tests/bot/markdownV2Fallback.spec.ts

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Walkthrough

The buyer notification flow now retries Telegram MarkdownV2 parse failures as plain text after removing escapes. Other errors remain unchanged. Tests cover fallback retries, action buttons, non-formatting errors, and safe localized messages.

Changes

MarkdownV2 fallback

Layer / File(s)	Summary
Fallback sender and buyer-flow wiring bot/messages.ts	MarkdownV2 parse errors trigger a logged plain-text retry. Other errors are re-thrown. beginTakeSellMessage uses the fallback-aware sender.
Fallback behavior tests tests/bot/markdownV2Fallback.spec.ts	Tests verify retry behavior, action-button delivery, non-formatting errors, and safe MarkdownV2 messages.

Estimated code review effort: 3 (Moderate) | ~20 minutes

Possibly related PRs

• lnp2pBot/bot#872: Both changes address MarkdownV2 formatting failures in the buyer-take flow and Farsi locale strings.

Suggested reviewers: luquitasjeffrey, matobi98

Poem

A rabbit found a broken mark,
And sent plain words into the dark.
The buttons stayed beside the note,
While escaped signs learned how to float.
“Parse again!” the rabbit cheered.

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly describes the primary fix: preserving taker message delivery when MarkdownV2 parsing fails.
Linked Issues check	✅ Passed	The changes satisfy issue #882 by adding a MarkdownV2 parse-error fallback, preserving safe formatting, and allowing action-button delivery.
Out of Scope Changes check	✅ Passed	The production and test changes are limited to the MarkdownV2 fallback behavior and its regression coverage.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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