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/types.ts

@@ -64,7 +64,6 @@ export interface Shop {
 export interface Bin {
   id: string;
   name: string;
-  location: string | null;
   capacity: number;
 }