Task/Issue URL:
https://app.asana.com/1/137249556945/project/1207418217763355/task/1216213420213818?focus=true

### Description

This PR submits new strings for a translation.

### Steps to test this PR

QA-optional

<!-- CURSOR_SUMMARY -->
---

> [!NOTE]
> **Low Risk**
> String-resource-only changes with no app logic; risk is limited to
translation or missing-locale fallback issues.
> 
> **Overview**
> Moves **Fire mode / Fire Tabs** UI copy out of `donottranslate.xml`
into the main translatable `strings.xml` resources so
Smartling/localization can ship it.
> 
> The same **15 string keys** (e.g. open in Fire tab, mode toggle
labels, empty state, promo, delete confirmation) are added to the
default `values/strings.xml` and mirrored across **~25 locale**
`values-*/strings.xml` files with translated text. English defaults are
unchanged in wording; only resource placement changes.
> 
> Also includes an unrelated **Latvian** copy tweak in `duckchat` for
`duckAiDefaultTogglePositionTitle` (“toggle position on new tab”).
> 
> <sup>Reviewed by [Cursor Bugbot](https://cursor.com/bugbot) for commit
3a1a226ce327aef20990536dfebf0c16e2fc448f. Bugbot is set up for automated
code reviews on this repo. Configure
[here](https://www.cursor.com/dashboard/bugbot).</sup>
<!-- /CURSOR_SUMMARY -->

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Co-authored-by: smartling <smartling@host-vm>