CSV import: surface skipped relationship identifiers (not-found & no-READ) in the import summary

Problem Statement

When a CSV import resolves relationship columns, related content can be silently dropped from the resulting relationships, with only a server-side Logger.warn and nothing surfaced in the import result shown to the user. There are two such cases in RelationshipUtil / the import flow:

1. Identifier not found — RelationshipUtil.filterContentlet logs "No contentlet found for identifier '…'" and skips it (pre-existing).
2. No READ permission — introduced in #35222 (PR #36425): related content the importing user cannot READ is filtered out via permissionAPI.filterCollection(...) in RelationshipUtil.getRelatedContentFromQuery.

In both cases the import reports success with silently incomplete relationships, and the user cannot tell a permission-filtered identifier apart from a genuinely missing one.

Acceptance Criteria

• When a relationship identifier is dropped during import (not found or filtered by permission), a warning/message is threaded back into the import result (e.g. via RelationshipProcessingBuilder / the ValidationMessages surfaced in the import summary), not just the server log.
• The message distinguishes "not found" from "no permission" so the user can act on it.
• Existing behavior (the relationship is still created for the resolvable/authorized identifiers; the row is not aborted) is preserved.

Context / Origin

Follow-up from PR #36425 (fix for #35222). The permission-filtering there was intentionally scoped to the import path and kept as filter-and-warn to avoid aborting import rows. This issue tracks improving visibility of both silent-drop cases together, since the not-found case has the same gap.

Relevant code:

• dotCMS/src/main/java/com/dotcms/util/RelationshipUtil.java — getRelatedContentFromQuery (permission filter) and filterContentlet (not-found skip)
• dotCMS/src/main/java/com/dotmarketing/util/ImportUtil.java — processRelationships / RelationshipProcessingBuilder (where warnings are surfaced to the import result)

dotCMS Version

Evergreen 26.06.21-01

Severity

Low — visibility/UX improvement; no data loss or security impact.

Links

Freshdesk ticket for the original issue:

https://dotcms.freshdesk.com/a/tickets/36035

Start with dotCMS/src/main/java/com/dotcms/util/RelationshipUtil.java, reading getRelatedContentFromQuery and filterContentlet to trace permission-filtered and not-found identifiers. Then inspect dotCMS/src/main/java/com/dotmarketing/util/ImportUtil.java, especially processRelationships and RelationshipProcessingBuilder; done means the import summary distinguishes both warnings while preserving resolvable relationships and row processing.