i18n(zh): AI translation update — sync with messages.pot (2026-06-13)

[mekarpeles]

Summary

Syncs the zh (Chinese) translation file with the current `messages.pot` template and fills in
previously untranslated strings.

AI attribution: All new translations in this PR were generated by `claude-sonnet-4-6`. They should
be reviewed by a native speaker before merging, particularly for tone and idiomatic accuracy.
Format strings (`%(name)s`, `%(count)d`, etc.) and HTML markup were preserved verbatim.

Changes

• Ran `scripts/i18n-messages update zh` to sync with current `messages.pot`
• Fixed 4 pre-existing HTML structure mismatches in existing translations
• Filling in ~465 previously untranslated msgid entries (in progress — draft until complete)
• Left fuzzy entries unchanged (marked for human review)

Validation

• `i18n-messages validate zh` — 0 errors ✓
• HTML structure tests — 67 passed ✓
• pre-commit — clean ✓

Reviewer guidance

Please spot-check translations for:

1. Accuracy of meaning (does the translation convey the intent?)
2. Natural phrasing (does it sound like UI text, not literal translation?)
3. Correct simplified Chinese usage
4. Preserved format strings and HTML

Native speakers: please edit the `.po` file directly on this branch.

🤖 Generated by `claude-sonnet-4-6`

[Copilot]

Copilot wasn't able to review any files in this pull request.