sonar(tools): long tail, 1 single finding

[github-actions]

Filed by tools/sonar-triage/sonar-triage.ps1. This issue is the ticket: see docs/adr/0016-sonar-issue-triage.md.

Goal

Clear 1 one-off SonarCloud findings under tools/, each the only
finding in its file. Grouped so they are one PR rather than 1.

Findings

Location	Rule	Message	Sonar
tools/corpus/seeder/MethodSeeder.cs:112	csharpsquid:S3220	Review this call, which partially matches an overload without 'params'. The partial match is 'string[] string.Split(char separator, int count, StringSplitOptions options = StringSplitOptions.None)'.	open

Acceptance criteria

1. Every finding above is either fixed, or added to tools/sonar-triage/policy.jsonc with
   verdict: accept and a reason citing an ADR or a ticket. A finding that no longer
   reproduces on HEAD is called out in the PR body, not silently dropped.
2. ./build.ps1 -Integration is green.
3. No #pragma warning disable, no coverage exclusion, no gate lowered.

How to fix

Point a session at this issue and say use equiv-sonar-fix.