feat: config loading and sqlite schema

server/src/config.ts

@@ -1,3 +1,7 @@
+import { mkdirSync, readFileSync, writeFileSync } from 'node:fs'
+import path from 'node:path'
+import crypto from 'node:crypto'
+
 export interface Config {
   dataDir: string
   artworkDir: string
@@ -5,3 +9,30 @@ export interface Config {
   port: number
   sessionSecret: string
 }
+
+export function loadConfig(env: Record<string, string | undefined> = process.env): Config {
+  const dataDir = env.DATA_DIR ?? path.resolve('data')
+  mkdirSync(dataDir, { recursive: true })
+  const artworkDir = path.join(dataDir, 'artwork-cache')
+  mkdirSync(artworkDir, { recursive: true })
+  return {
+    dataDir,
+    artworkDir,
+    dbPath: path.join(dataDir, 'record-shop.db'),
+    port: Number(env.PORT ?? 3000),
+    sessionSecret: getOrCreateSecret(dataDir),
+  }
+}
+
+function getOrCreateSecret(dataDir: string): string {
+  const secretPath = path.join(dataDir, 'session-secret')
+  try {
+    const existing = readFileSync(secretPath, 'utf8').trim()
+    if (existing) return existing
+  } catch {
+    // first boot — create below
+  }
+  const secret = crypto.randomBytes(32).toString('hex')
+  writeFileSync(secretPath, secret, { mode: 0o600 })
+  return secret
+}