Search display name overrides in user fuzzy search

[skyfallwastaken]

Summary of the problem

User fuzzy search did not consider custom display name overrides, so searching for the name shown in the UI could fail to find the corresponding user.

Describe your changes

• Include display_name_override in fuzzy-search candidate selection.
• Rank exact, prefix, and substring display-name matches using the same tiers as other username fields.
• Add regression coverage for case-insensitive exact and substring searches.

Screenshots / Media

No visual changes.

[Copilot]

Copilot was unable to review this pull request because the user who requested the review has reached their quota limit.

[greptile-apps]

Greptile Summary

The PR makes display-name overrides searchable through the existing ranked fuzzy-search flow and fixes the previously reported unindexed substring scan.

• Adds display-name overrides to candidate selection and exact, prefix, and substring ranking.
• Adds a concurrent GIN trigram index for display-name substring searches.
• Adds regression coverage for case-insensitive exact and substring matches.

Confidence Score: 5/5

The PR appears safe to merge.

No blocking failure remains.

Important Files Changed

Filename	Overview
app/models/concerns/user_fuzzy_search.rb	Adds display-name override candidate matching and ranking consistently with existing searchable username fields.
db/migrate/20260804184518_add_trgm_index_to_users_display_name_override.rb	Adds the appropriate concurrent GIN trigram index for the new case-insensitive substring predicate.
db/schema.rb	Records the new migration version and display-name trigram index.
test/models/concerns/user_fuzzy_search_test.rb	Covers case-insensitive exact and substring searches against display-name overrides.

_{Reviews (3): Last reviewed commit: "Index display name overrides for fuzzy s..." | Re-trigger Greptile}