Refactor supplier analysis and product handling

- Updated `SupplierAnalysisResult` to include a `product` field and modified related tests.
- Refactored `addRowsSheet` to accommodate changes in the product structure.
- Enhanced UPC file analysis to utilize a new `toSupplierInputRecord` function for cleaner record creation.
- Introduced new types for supplier input records and product observations.
- Updated frontend components to handle new product details and analysis history.
- Improved database writing functions to streamline run completion and error handling.
- Added new API endpoints for product details and adjusted routing in the frontend.

CLAUDE.md

@@ -90,6 +90,7 @@ Tracks competitor sellers across ASINs. Fetches storefronts, checks sellability
 | `src/config.ts` | Env var loading via `Bun.env` |
 | `src/db/index.ts` | Drizzle Postgres connection (shared pool) |
 | `src/db/schema.ts` | Drizzle schema for all tables |
+| `src/db/persistence.ts` | Product, observation, unified run-item, UPC resolution, and revision persistence |
 | `src/integrations/keepa.ts` | Keepa API: batch ASIN fetch, UPC lookup, auto rate-limiting |
 | `src/integrations/sp-api.ts` | SP-API: sellability, pricing+fees, UPC catalog lookup |
 | `src/integrations/cache.ts` | Redis caching (24h TTL for lead-list; 12h for mid-range) |
@@ -112,4 +113,6 @@ Tracks competitor sellers across ASINs. Fetches storefronts, checks sellability
 - The supplier UPC pipeline must not call LM Studio.
 - Supplier UPC files resolve UPC/EAN through SP-API catalog lookup first; Keepa UPC lookup is fallback only (no-match or request-failure cases).
 - Supplier workbook output must keep `Ranked Leads`, `Skipped`, and `Summary` sheets.
+- Treat `products.asin` as the canonical normalized product identity; UPC values belong only in identifier and resolution records.
+- Store time-varying data in observations or revisions and retain run history rather than overwriting prior analysis.
 - When changing UPC supplier behavior, cover SP-API UPC parsing, deterministic scoring, and workbook export with `bun test`.