Improve auditlog table and model

[Simrayz]

Scope and purpose

Resolves #3757

Adds sortable display name columns (actor_sortkey, object_sortkey, target_sortkey) to auditlog entries. This enables sorting and searching on these columns, and allows showing entity links when the referenced objects still exist.

Key decisions:

• Sortkeys preserve display names after objects are deleted
• Batch resolution pattern loads entities without causing N+1 queries
• Created API v2 to add entity linking while maintaining v1 backward compatibility

API v2 added: New /api/2/auditlog/ endpoint returns actor, object, and target as objects with {name, url} for entity linking. The existing /api/1/auditlog/ endpoint continues to return plain strings and remains unchanged. The web UI now uses v2.

Migration note: The backfill operation may take some time on deployments with millions of log entries.

Testing backfill and entity links

Filter by verb=edit-account-add-org, verb=disable-interface, verb=create-netbox, verb=delete-netbox, or verb=create-account to observe:

• Clickable links when entities still exist - The actor/object/target names are clickable and navigate to the entity's detail page (e.g., clicking an account name goes to the account detail page)
• Placeholder text when entities are deleted - Shows model_name (ID) format (e.g., account (123)) since the object no longer exists, but the sortkey preserved the searchable text

Contributor Checklist

Every pull request should have this checklist filled out, no matter how small it is.
More information about contributing to NAV can be found in the
Hacker's guide to NAV.

• Added a changelog fragment for towncrier
• Added/amended tests for new/changed code
• Added/changed documentation
• Linted/formatted the code with ruff, easiest by using pre-commit
• Wrote the commit message so that the first line continues the sentence "If applied, this commit will ...", starts with a capital letter, does not end with punctuation and is 50 characters or less long. See https://cbea.ms/git-commit/
• Based this pull request on the correct upstream branch: For a patch/bugfix affecting the latest stable version, it should be based on that version's branch (<major>.<minor>.x). For a new feature or other additions, it should be based on master.
• If applicable: Created new issues if this PR does not fix the issue completely/there is further work to be done
• If it's not obvious from a linked issue, described how to interact with NAV in order for a reviewer to observe the effects of this change first-hand (commands, URLs, UI interactions)
• If this results in changes in the UI: Added screenshots of the before and after
• If this adds a new Python source code file: Added the boilerplate header to that file

[github-actions]

Test results

    21 files      21 suites   25m 19s ⏱️
 2 948 tests  2 948 ✅ 0 💤 0 ❌
16 476 runs  16 476 ✅ 0 💤 0 ❌

Results for commit 35e0dc7.

♻️ This comment has been updated with latest results.

[codecov]

Codecov Report

❌ Patch coverage is 92.30769% with 8 lines in your changes missing coverage. Please review.
✅ Project coverage is 63.33%. Comparing base (936bb62) to head (35e0dc7).
⚠️ Report is 27 commits behind head on master.

Files with missing lines	Patch %	Lines
python/nav/auditlog/api.py	91.66%	7 Missing ⚠️
python/nav/models/manage.py	50.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #3776      +/-   ##
==========================================
+ Coverage   63.23%   63.33%   +0.10%     
==========================================
  Files         617      618       +1     
  Lines       45662    45813     +151     
  Branches       43       43              
==========================================
+ Hits        28874    29016     +142     
- Misses      16778    16787       +9     
  Partials       10       10              

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.

[sonarqubecloud]

Quality Gate passed

Issues
1 New issue
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud