Add scan result summary line showing passed/failed/warning counts

[KryptosAI]

Summary

Add a summary line at the end of every scan output showing "X servers passed, Y failed, Z warnings" for quick scanning of results.

Files to modify

• src/reporters/terminal.ts

What to change

1. After all per-server results are printed, add a divider line and a summary block.
2. Count servers by their worst result: all checks passed → "passed", any FAIL → "failed", only WARN → "warnings".
3. Print the summary like:

   ─────────────────────────────
   3 servers scanned: 1 passed, 1 failed, 1 warnings
   

4. Color-code the numbers: green for passed, red for failed, yellow for warnings.
5. If --json output is active, include the counts in the JSON payload instead.

Expected behavior

Running any scan command prints a clear one-line summary at the very end of output.

Estimated time

~15 minutes

[albatrossflyon-coder]

Hi! I'd like to work on this one.