⚡ Batch insert divisions update in receiver DB

[iwismer]

💡 What: Batched INSERT OR REPLACE INTO divisions statements into chunked multi-row queries (chunk size 100) instead of executing single-row stmt.execute in a loop.

🎯 Why: Replaced the N+1 query pattern when updating divisions in services/receiver/src/db.rs (replace_divisions and replace_rd_data) to reduce SQLite statement execution overhead.

📊 Measured Improvement: Replaced 10,000 single-row executions with 100 chunked multi-row batch executions per 10k divisions payload.

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PR created automatically by Jules for task 9411510292995909670 started by @iwismer

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