fix(parser): custom format doesn't match 'xvid' at end of release name

[Starosdev]

Bug Report

Upstream: Radarr#6824 (confirmed)

Environment

• Affected: Production
• Component: Backend / Parser

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Description

Custom format conditions for the term "xvid" do not match when it appears at the very end of a release name. The regex boundary likely fails at end-of-string.

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Acceptance Criteria

• Custom format term matching works at end of release name
• Existing matches are not affected