Fix: Sort observations by resultTime in descending order

[ram-from-tvl]

Fixes #5

Changes Made

Added ORDER BY resulttime DESC clause to the SQL query in the ObservationQuery.to_sql() method (util.py).

This ensures observations are returned in descending order by resultTime, with the newest observations appearing first.

Why This Approach

• The sorting is applied at the database level (TimescaleDB/PostgreSQL) for optimal performance
• Using resultTime as the sort key aligns with the observation data model
• Descending order (newest first) is the most common use case for time-series data
• The ORDER BY clause is placed before LIMIT/OFFSET to ensure proper pagination

Resolves #5

[Copilot]

Pull request overview

This pull request adds sorting functionality to observation queries by implementing an ORDER BY resulttime DESC clause at the database level. The change addresses issue #5, which reported that observations were being returned in an unsorted order, making it difficult for API consumers to work with time-series data predictably.

Changes:

• Added ORDER BY resulttime DESC to the SQL query builder in ObservationQuery.to_sql() method to ensure all observation queries return results sorted by newest first

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[ram-from-tvl]

Hi @EHJ-52n @SpeckiJ
please review this PR and let me know if more changes are required.
Thankyou!