docs: fix recovery search commands

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Summary

Fix outdated mempalace search syntax in the index metadata recovery guide.

The guide used --query and --limit, but the current CLI accepts the query as a positional argument and uses --results.

Impact

Operators following the recovery procedure can now run the documented verification command without an argparse error.

Validation

• Confirmed the previous command fails with an unrecognized-arguments error.
• Confirmed mempalace search --help documents the positional query argument and --results option.
• Ran git diff --check.