fix(demo): implement Place Autocomplete for Region Search

[henrikvalv3]

Background & Motivation
Previously, the Region Search feature relied on users free-typing a region name and manually selecting an administrative level (e.g., "Manhattan" + "Locality"). This resulted in naming collisions (e.g., querying Manhattan, KS instead of Manhattan, NY).

Changes Made

• UI Update: Replaced the free-text input and dropdown with the Google Maps PlaceAutocompleteElement component, restricted to the user's active country.
• Exact ID Querying: The application now extracts the exact Place ID and types array from the selected prediction, maps the type to the correct BigQuery column, and passes the ID into the SQL query.
• Schema Handling: Updated state.js and query.js to correctly distinguish between BigQuery STRING fields (e.g., administrative_area_level_1_id for states/countries) and ARRAY fields (e.g., locality_ids for cities), generating the appropriate = or UNNEST() SQL syntax to prevent column-not-found errors.
• Dynamic Map Framing: Leveraged the viewport property from the Places API to perfectly fit the map bounds to the selected region's true geometry, preventing the map from over-zooming on a single center coordinate.
• Minor UX Fix: Ensure that if a user types a brand name into the brand filter input but forgets to click the "+" add button, the pending input is still appended and included in the query.

Impact
This guarantees accuracy when searching for administrative areas, removes the cognitive load on the user to guess the correct region type, and provides a much smoother map zooming experience.