refactor: move ellipsis and punctuation into i18n translation strings (#8573)

## Summary

Move ellipsis and punctuation characters into i18n translation strings
for proper internationalization support.

## Changes

- Add 12 new translation keys with punctuation included:
- Placeholder keys with trailing ellipsis (e.g.,
`searchNodesPlaceholder: "Search Nodes..."`)
  - `downloadWithSize` with interpolation: `"Download ({size})"`
  - `completedWithCheckmark`: `"Completed ✓"`
- Prompt keys with colons (e.g., `enterNewNamePrompt: "Enter new
name:"`)
- Update 20 files to use new translation keys instead of string
concatenation

## Review Focus

This eliminates string concatenation patterns like `$t('key') + '...'`
that break proper internationalization, since different languages may
use different punctuation or may not need ellipsis/colons in the same
contexts.

Fixes #7333


<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit

* **Chores**
* Standardized localization across the app: unified search placeholders
and input hints; updated dialog prompt texts for renaming,
saving/exporting, and related prompts.
* **New Features**
  * Download buttons now show file size via localized text.
  * Completed status displays a localized label with a checkmark.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-8573-refactor-move-ellipsis-and-punctuation-into-i18n-translation-strings-2fc6d73d365081828ad3f257bcac7799)
by [Unito](https://www.unito.io)

src/platform/settings/components/SettingDialogContent.vue

@@ -18,7 +18,9 @@
         <SearchBox
           v-model:model-value="searchQuery"
           class="settings-search-box mb-2 w-full"
-          :placeholder="$t('g.searchSettings') + '...'"
+          :placeholder="
+            $t('g.searchPlaceholder', { subject: $t('g.settings') })
+          "
           :debounce-time="128"
           autofocus
           @search="handleSearch"