[MEDIUM] Missing transactions in bulk_import, clear_all_data, data_quality

[matthewod11-stack]

Description

Bulk operations write row-by-row with no transaction wrapping. Partial failures commit half-imported / half-deleted state. By contrast documents.rs correctly uses pool.begin().

Current State

• src-tauri/src/bulk_import.rs:106-113 — clear_all_data issues 5 sequential DELETEs, no transaction. Interrupted run leaves DB inconsistent.
• src-tauri/src/bulk_import.rs — import_reviews_bulk, import_employees_bulk insert rows individually, no transaction.
• src-tauri/src/data_quality.rs — dedupe / merge operations run multiple writes without atomicity.

Suggested Fix

• In each bulk function, start let mut tx = pool.begin().await?; → use tx for all writes → tx.commit().await? at the end.
• On any write error, drop tx (rollback is automatic).
• For very large imports (>10k rows), consider chunked transactions (e.g., 1000 rows per COMMIT) to bound memory/journal size.

Verification

• cargo test bulk_import passes + add a test that simulates mid-import error and verifies no partial rows remain.
• Manual: import a CSV, kill the app mid-import → next launch shows empty or pre-import state, not partial.

Automation Hints

scope: src-tauri/src/bulk_import.rs, src-tauri/src/data_quality.rs
do-not-touch: src-tauri/src/documents.rs (already correct, use as reference)
approach: add-declarations
risk: medium (transaction semantics)
max-files-changed: 2
blocked-by: none
bail-if: none

Priority

Medium — data-integrity protection for import failure modes.