🚀 Feature: Add "is not" operator to work item filters #10228

Is there an existing issue for this?

• I have searched the existing issues

Summary

Add an "is not" operator (and "is none of" for multi-select) to the work item filters. Today the operator dropdown only offers "is", "is any of" and "between", so there is no way to express "everything except X", for example all work items whose state is not Closed.

Why should this be worked on?

Excluding a value currently means ticking every other value by hand with "is any of", and re-doing it whenever a new state, label or member is added. Hiding closed or cancelled work is a very common need.

The groundwork already seems to exist in the community edition:

• The API filter backend already evaluates {"not": {...}} nodes (apps/api/plane/utils/filters/filter_backend.py).
• The filter expression types already define a NOT group.
• The frontend has allowNegative, negOperatorLabel, NEGATED_OPERATOR_LABELS_MAP and an isNegation argument threaded through the filter store, but they are currently stubbed out (allowNegative: false, an empty negated labels map, getOperatorForPayload always returning isNegation = false, and the work item filter adapter only converting AND groups).

Question

Is negation intentionally held back from the community edition? If it is not, I would be glad to contribute a PR that wires up the existing scaffolding (labels, getOperatorForPayload, wrapping a condition in a NOT group in the store, and NOT support in the work item filter adapter) with tests. If it is reserved for a paid edition, I will not pursue it.