fix: refine existing locale translations (4/3)

[eliotcougar]

Context and series

Follow-up to #6005.

This is the unplanned part 4 of 3 in the localization series originally extracted from #6021. It further separates the XML-only translation and wording work that was still bundled into the previous combined Part 3 draft in #6044.

• Part 1 — fix: sync locale resources and translations (1/3) #6024 (merged): synchronized the locale catalogs, filled missing translations, corrected divergent meanings, and marked invariant technical values non-translatable.
• Part 2 — fix: localize user-facing and accessibility text (2/3) #6025 (merged): extracted hardcoded user-facing text, introduced dedicated accessibility descriptions, and localized the resulting resources.
• Part 3 — fix: honor the selected app locale everywhere (3/3) #6047: makes the selected app language authoritative in Android resource contexts.
• Part 4 — this PR: contains only standalone translation and wording corrections to existing XML resources.

Why this is separate

The combined draft mixed locale infrastructure, service/UI data-flow work, new resources, and translation polish. The changes here require no Kotlin, Gradle, manifest, or UI-layout changes and can be reviewed entirely as old/new resource values.

Translation and wording improvements

Complete catalog review

• Reviews the complete locale catalogs for awkward, overly literal, or calque-like wording.
• Uses more natural established terms and phrases in Arabic, Bangla, Bakhtiari, Persian, Russian, Vietnamese, Simplified Chinese, and Traditional Chinese.
• Preserves xray-core identifiers, protocol names, raw keys, syntax examples, and other strictly technical terminology where translation would reduce clarity.
• Corrects stale Arabic labels that still described numbered workflow steps.
• Corrects misleading, unnatural, or inconsistent labels and status messages throughout the maintained catalogs.

Settings and menu wording

• Clarifies that per-app proxy auto-selection selects apps that should be proxied.
• Shortens Subscription group settings to Subscriptions across locales.
• Localizes “format” in the DNS hosts title while retaining the literal domain:address,… syntax.
• Standardizes URL capitalization.
• Simplifies the all-profile clipboard export label.
• Clarifies the connected-state prompt and uses a line break where the combined text would be too long.

Distinguish profile export actions

The profile More menu previously had two clipboard actions whose labels were insufficiently distinct in several locales.

• Copy profile link copies the selected profile's share/import URI.
• Copy full configuration copies the fully generated core configuration.

Both actions now use this distinction consistently in every maintained locale.

Focus of this extraction

Only these nine files change:

• values/strings.xml
• values-ar/strings.xml
• values-bn/strings.xml
• values-bqi-rIR/strings.xml
• values-fa/strings.xml
• values-ru/strings.xml
• values-vi/strings.xml
• values-zh-rCN/strings.xml
• values-zh-rTW/strings.xml

This PR deliberately excludes every resource change that depends on code outside XML.