Orderby expression

[den-crane]

closes: #97

Why

My Clickhouse's log tables require very specific ORDER BY expression (toStartOfHour(timestamp) desc,timestamp desc) .

What

This PR adds ORDER_BY_expression entity to Clickhouse Sources (UI/tables/migration).
This ORDER_BY_expression is used by default in Logs also it displayed in the new InputBox at the right from Columns selector. This input allows to define ad-hoc orderby. Also this input box state will be stored in View along with ColumnsSelector, etc.
Plus tests.

References

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100% vibe-coded by CC.
Later I am going to add a feature for changing this Logs viewer's ad-hoc ORDER_BY_expression by clicking to table's headers.

[HumanUser]

Thanks for the contribution - I agree that order_by_expression makes sense at the source level, especially for ClickHouse where time-based ordering may require optimization like:

toStartOfHour(timestamp) DESC, timestamp DESC

That’s a valid source-level optimization.

However, I’m less convinced about arbitrary user-level ORDER BY overrides in a log viewer. Telescope is primarily designed for time-ordered log exploration. Allowing custom expressions moves it closer to a generic data explorer, which may not be the intended direction.

There are also some concerns:

• Security - raw SQL concatenation increases injection surface.
• Performance - users can introduce expensive or non-indexed sorts.
• If we keep user-level overrides, this should probably be permission-gated and/or validated. - while i still not use I want to do itg.

Architecturally, I’d also avoid hardcoding something like:

source.type == 'clickhouse'

Instead, a capability-based approach (e.g. supportsOrderByExpression) would be cleaner and more extensible, especially since this does not apply to Docker/K8s sources.

Let’s align on product direction before finalizing.

p.s.
All these question ask "why" there is opening-an-issue-first note in contribution guide: https://github.com/iamtelescope/telescope?tab=contributing-ov-file#opening-an-issue-first

[den-crane]

However, I’m less convinced about arbitrary user-level ORDER BY overrides in a log viewer.

Right, I don't need it that much myself.
Generally, I was inspired by the Hyperdx UI, it allows to define a query ORDERBY in ad-hoc manner.

How about I move input box and everything under RAW QUERY?
Input box will be invisible till the raw query enabled and it will be secured by the raw query privilege.