Complete Simplified Chinese translations and localize runtime messages

[0x00kh]

What does this PR do?

Completes the remaining Simplified Chinese interface translations and fixes runtime messages that bypassed localization entirely.

• Translate 49 existing English placeholders in Settings, update checks, and CPU/memory/process monitoring; improve terminology, permission instructions, and Chinese punctuation.
• Route scan labels and cleanup/tool errors through String(localized:), including sandbox caches, legacy DerivedData, unsafe paths, Docker, simulator runtimes, Homebrew, and app-signature errors.
• Add 43 runtime-message keys and their Simplified Chinese translations. Add English fallback entries to the other language catalogs to preserve the project's key-parity invariant; this does not claim to complete those translations.
• Add regression coverage for untranslated Simplified Chinese values and interpolated runtime keys. Make affected cleanup tests locale-independent and identify cleanup fixtures by path rather than translated display names.

File names, paths, commands, and raw external-tool output remain unchanged. Cleanup decisions, deletion safety checks, and command execution are unchanged.

Type of change

• Bug fix
• New feature
• Performance improvement
• UI/UX enhancement
• Documentation
• Other (describe)

Testing

• Compile all application Swift sources to an object file with Swift 5 language mode and the arm64-apple-macos13.0 target; no new compiler warnings compared with the baseline.
• Extract localization keys using the Swift compiler and verify that all 43 new keys match actual interpolation output, with no missing linguistic interface keys in the catalogs.
• Validate all 13 catalogs: 900 matching keys each, compatible format specifiers, no duplicate keys, and no empty values.
• Verify that the only unchanged Simplified Chinese values are the five intentional product names/technical abbreviations.
• Exercise Simplified Chinese bundle lookup and native Foundation interpolation, including paths and Int32 exit codes.
• Parse the modified Swift tests and run git diff --check.
• Tested on macOS Ventura (13.x)
• Tested on macOS Sonoma (14.x)
• Tested on macOS Sequoia (15.x)

Full XCTest execution, Xcode app packaging, and visual UI verification were not available locally because only Command Line Tools are installed. The macOS 13 deployment target above is a compilation check, not a runtime test on Ventura.

Screenshots

Not captured; this PR changes localized text and localization routing without changing layouts.