Add Python version of Top Repeaters script and update README

[nullrouten0]

Motivation

• Provide a Python CLI equivalent so operators can compute the map's "Top Repeaters" leaderboard outside the Node environment.
• Make the query logic explicit and reusable in Python while preserving the exact tile-based coverage counting used by the map.

Description

• Added server/scripts/top-repeaters-from-samples.py, a Python CLI that mirrors the Node script and computes Top Repeaters from GET /get-samples by grouping samples by 6-char geohash tile, deduplicating repeater IDs per tile, counting tile coverage per repeater, and sorting descending.
• The script supports the same options as the Node tool: --url, --prefix, --limit, and --json and tolerates payload variations by reading name/hash and metadata.path/path/legacy rptr fields.
• Updated README.md Top Repeaters examples to include python3 scripts/top-repeaters-from-samples.py usage alongside the existing Node commands.

Testing

• Ran python3 -m py_compile server/scripts/top-repeaters-from-samples.py which succeeded without syntax errors.
• Ran python3 server/scripts/top-repeaters-from-samples.py --help which printed the CLI help text successfully.

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