i18n(cs): AI translation update — sync with messages.pot (2026-06-16)

[mekarpeles]

Summary

Syncs the Czech (cs) 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 cs to sync with current messages.pot
• Cleared 112 entries with format-string mismatches (placeholder incompatibilities from prior translations)
• Filling in untranslated msgid entries in batches (work in progress)

Validation

• i18n-messages validate cs — 0 errors ✓
• i18n-messages compile cs — compiled successfully
• pre-commit run --files openlibrary/i18n/cs/messages.po — 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 plural forms for Czech (3 plural forms)
4. Preserved format strings and HTML

🤖 Generated by claude-sonnet-4-6

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