feature: multi-language property search

[nanaf6203-bit]

Summary

Property search is English-keyword only.

Affected area

• i18n-aware search using localised property names, cities, types. Cover en/es/fr minimum.

Acceptance criteria

• Implement the change described above.
• Add or update unit/e2e tests locking in the new behaviour.
• Update README / docs to reflect the new state.

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Filed automatically as part of the PropChain code-review sweep.