cli(test): add --verbose flag to list test case names

[twmb]

Summary

• Adds a -v/--verbose flag to the test CLI command
• When enabled, prints individual test case names before execution, similar to go test -v
• Useful for identifying commented-out tests, misnamed files, or which test is running

Test plan

• Existing test command tests pass with updated signature
• Manual verification with rpk connect test -v ./path/to/tests/...

Closes redpanda-data/connect#893

🤖 Generated with Claude Code

[andrewhsu]

@twmb rebase this PR with latest from main to get the updated claude-code-review.yml workflow that has access to the api key.

[claude]

Commits
LGTM

Review
Adds a --verbose/-v flag to the test CLI command that prints test case names before execution. The flag is cleanly threaded through RunAll, existing call sites and tests are updated to match the new signature.

LGTM