fix(dex): surface best_orders failures; CTA to Maker; localized empty states

[CharlVS]

This PR addresses best_orders error handling and improves UX for empty orderbooks.

Changes

• Propagate best_orders failures (no longer masked as empty).
• Map P2P "No response from any peer" (including wrapped Exception text) to "no orders" so the UI shows an empty state instead of an error.
• Add debug-only failure simulator gated by app_config.dart toggles (kSimulateBestOrdersFailure, rate configurable).
• Taker: show CTA to create a Maker order when no swap offers are available.
• Bridge: show CTA when no cross-network routes are available.
• Add locale keys: dexNoSwapOffers, bridgeNoCrossNetworkRoutes and wire them in the UI.

Other

• Keep best_orders disabled outside Swap/Bridge pages.
• Maintain retry logic already present in Mm2Api.

Screenshots

NB!

Disable the failure simulator before merge.

Please review error mapping and copy.

[coderabbitai]

Important

Review skipped

Auto reviews are disabled on base/target branches other than the default branch.

Please check the settings in the CodeRabbit UI or the .coderabbit.yaml file in this repository. To trigger a single review, invoke the @coderabbitai review command.

You can disable this status message by setting the reviews.review_status to false in the CodeRabbit configuration file.

✨ Finishing touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Post copyable unit tests in a comment
• Commit unit tests in branch fix/order-book-retry

---

Thanks for using CodeRabbit! It's free for OSS, and your support helps us grow. If you like it, consider giving us a shout-out.

❤️ Share

• X
• Mastodon
• Reddit
• LinkedIn

_{Comment @coderabbitai help to get the list of available commands and usage tips.}

[smk762]

lgtm, thanks!