feat: add funny startup message for Teamleader agent runner

[JOORVIS]

Summary

• Add a deterministic funny startup line to app:workflow:run-teamleader-agent before existing processing.
• Keep all existing Teamleader runner behavior unchanged (dispatching, logging, exit codes, and no-config handling).
• Add unit tests for both no-config and with-config flows, asserting the funny message output and dispatch behavior.

Test plan

• Run mise run tests in an environment where mise targets this workspace checkout.
• Optionally run focused test: tests/Unit/Workflow/TeamleaderAgentRunnerCommandTest.php.

Closes #3