FIX: Improve errors for duplicate tags (issue #738)

[VisLab]

The duplicate tag errors were not reporting where the error occurred (e.g., line numbers in tsv and key values in json), only the file in which they occurred and what tags were duplicated.

[github-actions]

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[Copilot]

Pull request overview

This PR improves duplicate-tag error reporting by ensuring duplicate-tag detection failures are returned as regular Issue objects (instead of thrown exceptions), so BIDS validators can attach context like TSV line numbers and sidecar key/file information.

Changes:

• Catch IssueError thrown during ParsedHedString normalization (e.g., duplicateTag) and return it via the parser’s standard [parsedString, errors, warnings] contract.
• Update BIDS JSON-driven tests to assert duplicateTag issues include tsvLine and/or sidecarKey/filePath, and add targeted regression cases.
• Adjust normalizer test expectations to align with the new non-throwing behavior (normalized output becomes undefined when parsing returns null).

Reviewed changes

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

File	Description
tests/jsonTestData/normalizerTests.data.js	Updates expected normalized output for duplicate-tag failures to match the parser’s new return behavior.
tests/jsonTestData/bidsTests.data.js	Adds/updates expected BIDS-wrapped issues so duplicate-tag errors include TSV line numbers and sidecar key/file context; adds regression tests.
src/parser/parser.js	Converts IssueError from normalized-form computation into returned parse issues so downstream callers can enrich them with BIDS context.