[AI-FSSDK] [FSSDK-12813] Normalize decision event campaign_id, variation_id, and entity_id

[jaeopt]

Summary

Normalize three decision-event ID fields uniformly across every decision type (experiment, feature test, rollout, holdout) in the event-builder layer. decisions[].campaign_id and impression events[].entity_id accept any non-empty string (IDs may be opaque, e.g. "default-12345", "layer_abc") and fall back to experiment_id only when empty, null, or missing; decisions[].variation_id retains the stricter numeric-string-only contract and falls back to null for any invalid input. The normalization path is silent and never drops or defers event dispatch.

Changes

• Added isNonEmptyString (used for campaign_id / entity_id) and isNumericString (used for variation_id) validators, plus normalizeCampaignId and normalizeVariationId helpers in the event builder, applied uniformly in makeDecisionSnapshot with no per-type branching.
• normalizeCampaignId returns the provided id unchanged when it is a non-empty string of any character content; otherwise substitutes experimentId when that itself is a non-empty string; otherwise returns null.
• normalizeVariationId returns the provided id unchanged only when it is a non-empty decimal-digit string; otherwise returns null.
• Impression entity_id reuses the normalized campaign_id value so the two fields are byte-identical on the wire.
• Audited existing event-builder tests per FR-011 — happy-path fixtures use valid IDs; invalid-input expectations updated to normalized values (non-numeric campaign_id / entity_id now passes through unchanged; non-numeric variation_id still normalizes to null).

Jira Ticket

FSSDK-12813

[coveralls]

coverage: 77.71% (+0.02%) from 77.691% — ai/jaeopt/FSSDK-12813-holdout-event into master

[Copilot]

Pull request overview

This PR updates the event-builder layer to normalize decision-event identifier fields consistently across all impression decision types (experiment, feature-test, rollout, holdout), ensuring wire payloads use numeric-string IDs when valid, and deterministic fallbacks when invalid.

Changes:

• Added numeric-string validation plus normalization helpers for decisions[].campaign_id/impression events[].entity_id (fallback to experiment_id or null) and decisions[].variation_id (fallback to null).
• Updated impression snapshot construction so events[].entity_id is byte-identical to decisions[].campaign_id.
• Updated/expanded tests to reflect the new normalization contract and adjusted fixtures to use numeric-string IDs for happy-path expectations.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated no comments.

File	Description
lib/optimizely/index.tests.js	Updates expected decision snapshot output so invalid/empty variation_id is asserted as null (normalized) rather than an empty string.
lib/event_processor/event_builder/log_event.ts	Implements normalization helpers and applies them in makeDecisionSnapshot, including ensuring entity_id matches normalized campaign_id.
lib/event_processor/event_builder/log_event.spec.ts	Updates existing fixtures to numeric-string IDs and adds comprehensive normalization contract tests across decision types and edge cases.

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