filter ingestor array on controlled_vocabulary list

[mikesndrs]

Checklist

• I have read and followed the CONTRIBUTING guide.
• I confirm that I have the authority necessary to make this contribution on behalf of its copyright owner and agree to license it to the TeSS codebase under the BSD license.

[Copilot]

Pull request overview

This PR extends the ingestor pipeline to optionally normalize certain array fields (e.g., target_audience, keywords) against a controlled vocabulary mapping, controlled via a new feature.controlled_vocabulary_vars setting.

Changes:

• Refactors auto-parsing logic into handle_auto_parsing and reuses shared mapping-loading via get_mapping.
• Adds handle_controlled_vocabulary and applies it to both event and material ingestion.
• Adds unit tests validating controlled-vocabulary behavior when the feature flag is enabled/disabled.

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 2 comments.

File	Description
test/unit/ingestors/ingestor_test.rb	Adds coverage for controlled-vocabulary normalization behavior.
lib/ingestors/material_ingestion.rb	Routes material ingestion through the new helper methods.
lib/ingestors/event_ingestion.rb	Routes event ingestion through the new helper methods.
lib/ingestors/auto_parsing.rb	Introduces shared mapping loader + controlled vocabulary normalization helper.

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