Group bins by letter, sort by number, drop location

Bins follow an A1/A2/B1 naming convention, so the Bins page now parses
the leading letter prefix as a row group and the trailing number as the
within-row order. Each letter starts a fresh grid section; bins whose
names don't match the pattern fall into a trailing "Other" bucket
sorted alphabetically.

Removes the optional location field from bins end to end: the API
client signatures, server POST/PATCH routes, both product-flow inline
creates, the dropdown labels, the ProductDetail bin row, and the
BinsView header line. The bootstrap query explicitly projects only
id/name/capacity so the dead column doesn't leak through.

The location column stays in the bins table on disk to avoid a
migration on existing deployments — it just isn't read or written.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

web/src/components/ProductDetail.tsx

@@ -45,7 +45,7 @@ export function ProductDetail({
     ["Shop", helpers.shopName(data, product.shopId)],
     ["Total cannabinoids", `${product.totalCannabinoids.toFixed(1)}%`],
     ["Purchase date", fmt.date(product.purchaseDate)],
-    ["Bin", bin ? `${bin.name} — ${bin.location}` : <span style={{ color: "var(--ink-3)" }}>—</span>],
+    ["Bin", bin ? bin.name : <span style={{ color: "var(--ink-3)" }}>—</span>],
     ["Audit cadence", `Every ${cfg?.cadenceDays ?? "—"} days · ${cfg?.auditMode ?? "—"}`],
     [
       "Cost per gram",