feat(cli): add --dry-run option to decision-log-prune (#720)

[harmehak0173]

Summary

Fixes #720.

Adds --dry-run\ to \doberman decision-log-prune\ so operators can preview how many resolved decision rows would be pruned by age and/or row budget without deleting them:

• Adds \dry_run: bool = False\ to \prune_decisions\ in \src/doberman/storage/log.py: executes the delete queries to count rows, then executes \�wait conn.rollback()\ instead of \�wait conn.commit()\ when \dry_run\ is \True.
• Adds --dry-run\ option to \decision_log_prune\ in \src/doberman/cli/main.py: prints \Would prune N row(s) (A by age, B over --max-rows).\ when \dry_run\ is \True, while preserving standard output when \False.
• Updates \docs/CLI.md\ options list for \decision-log-prune.
• Adds integration tests in \ ests/integration/test_decision_log.py\ verifying that dry-run counts match a subsequent real prune and database rows remain unchanged after dry run.
• Adds CLI integration test in \ ests/integration/test_cli_views.py\ verifying preview output and database persistence.