Clear proposal resource and task overrides

Feature Request: Clear proposal resource and task overrides

Summary:
Enable users to remove resource field overrides and task field overrides from a proposal after they have been applied. This feature should allow users to reset overridden values efficiently so the proposal can return to its default or system-driven values without requiring manual updates field by field.

Problem Statement:
Currently, if a user applies a fee override to resources or task fields on a proposal and later decides that the override is no longer needed, there is no simple way to clear it. This creates unnecessary manual work, increases the risk of errors, and makes it difficult to restore the original proposal settings accurately.

Proposed Solution:
Allow users to clear resource field overrides and task field overrides directly within the proposal. The system should support removing previously entered override values without deleting the underlying resource or task data. When an override is cleared, the affected field should revert to its default calculated or inherited value. The experience should make it clear which fields are overridden and provide an efficient way to remove one or multiple overrides as needed.

Benefits:
Reduces manual effort when adjusting proposal pricing or staffing details. Improves accuracy by allowing users to safely return to default values without re-entering data. Increases flexibility for proposal management by making it easier to test, revise, and undo override decisions.