feat: add software_hashes table schema and reimport pipeline

- Add softwareHashes Drizzle model (download_id PK, md5, crc32,
  size_bytes, inner_path, updated_at)
- Update import_mysql.sh to reimport from JSON snapshot after DB wipe
- Add pnpm scripts: update:hashes, export:hashes
- Create data/zxdb/ directory for JSON snapshot storage

claude-opus-4-6@MacFiver

src/server/schema/zxdb.ts

@@ -1,4 +1,4 @@
-import { mysqlTable, int, varchar, tinyint, char, smallint, decimal, text, mediumtext, longtext } from "drizzle-orm/mysql-core";
+import { mysqlTable, int, varchar, tinyint, char, smallint, decimal, text, mediumtext, longtext, bigint, timestamp } from "drizzle-orm/mysql-core";
 
 // Minimal subset needed for browsing/searching
 export const entries = mysqlTable("entries", {
@@ -646,3 +646,16 @@ export const zxsrScores = mysqlTable("zxsr_scores", {
   score: varchar("score", { length: 100 }),
   comments: text("comments"),
 });
+
+// ---- Derived tables (managed by update scripts, not part of ZXDB upstream) ----
+
+// Stores MD5, CRC32 and size of the inner tape file extracted from download zips.
+// Populated by bin/update-software-hashes.mjs; survives DB wipes via JSON snapshot.
+export const softwareHashes = mysqlTable("software_hashes", {
+  downloadId: int("download_id").notNull().primaryKey(),
+  md5: varchar("md5", { length: 32 }).notNull(),
+  crc32: varchar("crc32", { length: 8 }).notNull(),
+  sizeBytes: bigint("size_bytes", { mode: "number" }).notNull(),
+  innerPath: varchar("inner_path", { length: 500 }).notNull(),
+  updatedAt: timestamp("updated_at").notNull().defaultNow(),
+});