Clean up TestServer test library

[oalders]

Two small, independent cleanups to the t/lib/TestServer* test library. Both are test-only and behavior-preserving.

Remove unused var in test lib

TestServer::perl_cmd declared my @libs = $self->lib_dirs; and never used it — the loop just below calls $self->lib_dirs directly.

Simplify dispatch() interface to ($c, $r)

dispatch() was called as dispatch($c, $r->method, $r->uri, $r), but $method and $uri are plain accessors on the request object $r. Pass only ($c, $r) and let each dispatch() implementation derive method/uri where it needs them. This also drops $method from TestServer::Reflect::dispatch, which unpacked it but never used it.

🤖 Generated with Claude Code

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 8.57%. Comparing base (b3d2084) to head (c678d98).

Additional details and impacted files

@@          Coverage Diff           @@
##           master     #87   +/-   ##
======================================
  Coverage    8.57%   8.57%           
======================================
  Files           1       1           
  Lines         338     338           
  Branches       86      86           
======================================
  Hits           29      29           
  Misses        304     304           
  Partials        5       5           

☔ 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.