Show trailing-separator scan path names

[dipeshbabu]

Summary

• preserve the final directory name when an absolute scan path ends in a separator
• keep parent path components out of progress output
• add focused CLI regression coverage

Root cause

The scan-scope formatter split absolute paths on / and selected the final segment. A trailing slash or backslash produced an empty final segment, so progress output omitted the scoped directory name.

Impact

Scans invoked with paths such as /workspace/service/ now report Running scan: service while retaining the existing parent-path redaction behavior.

Overlap check

Searched open issues and pull requests for trailing-separator scan paths, scan progress path display, and the affected helper name. The current open PRs are unrelated.

Validation

• pnpm dlx bun test --timeout 30000 ./tests-ts/cli.test.ts (85 passed)
• pnpm exec tsc --noEmit
• pnpm exec prettier --check src/cli.ts tests-ts/cli.test.ts
• git diff --cached --check