Event Lineage: Create Transform Function for Suffix Filter

Problem
Transform functions are how we track changes to eventtypes as events flow through the system. To support the suffix filter, we should implement a transform function to represent how a given eventtype becomes "narrower" as it passes the filter. Specifically, this transform function should (for each attribute set in the suffix filter):

1. Check if the attribute is already set. If it is and does not have the expected prefix from the filter, return a nil eventtype to model no events passing this filter
2. If the attribute is not already set, set it to the value expected by the filter, along with an empty variable for the prefix {x}.
3. If the attribute is compatible with the value required by the filter, but the filter provides more information, update the value to include the filter value. For example, if the value is currently {x}bc, where {x} is a variable, and the suffix filter is abc, then we can update the value to be {x}abc. Similarly, if the current value is abc{x}, and the suffix filter is de, then we can update the value to be abc{x}de.
4. If the prefix matches the value, but provides no new information, do not change anything. For example, if the value is abc, and the suffix is bc, then there is no need to make any change

Persona:
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Exit Criteria
A measurable (binary) test that would indicate that the problem has been resolved.

Time Estimate (optional):
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Additional context (optional)
Add any other context about the feature request here.

No file or test is named; begin by locating the event-lineage transform functions and the suffix-filter implementation in the Go repository. Compare existing transform behavior with the four cases in the issue, then add coverage showing compatible attributes are narrowed correctly and incompatible attributes produce no event type.