prevents trim is not a function exception

[FabricioFFC]

Summary

Prevents trim is not a function exception when user_id/device_id is not a string.

[macroscopeapp]

Prevent trim-is-not-a-function exceptions by coercing and trimming non-string identifiers in Exposure.canonicalize in exposure.ts

Update Exposure.canonicalize to coerce user_id, device_id, and variant.key with String(...) before trimming; add tests verifying numeric user_id and device_id do not throw in exposure-filter.test.ts.

📍Where to Start

Start with Exposure.canonicalize in exposure.ts.

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Macroscope summarized 390a025.