feat(attachments): depolama soyutlaması, içerikten tür tespiti, sharp/HEIC dönüşümü ve yetkili dosya servisi

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/lib/storage/local.ts

@@ -0,0 +1,37 @@
+import { randomBytes } from "node:crypto";
+import { mkdir, readFile, rename, rm, writeFile } from "node:fs/promises";
+import path from "node:path";
+import { isValidStorageKey, type StorageDriver } from "./types";
+
+/** Yerel disk sürücüsü. Yazma atomiktir (geçici dosya + rename); yarım dosya servis edilmez. */
+export function createLocalDriver(baseDir: string): StorageDriver {
+  const root = path.resolve(baseDir);
+
+  function resolve(key: string): string {
+    if (!isValidStorageKey(key)) throw new Error(`Geçersiz depolama anahtarı: ${key}`);
+    const full = path.resolve(root, key);
+    if (!full.startsWith(root + path.sep)) throw new Error("Depolama kökü dışına çıkılamaz.");
+    return full;
+  }
+
+  return {
+    async put(key, data) {
+      const full = resolve(key);
+      await mkdir(path.dirname(full), { recursive: true, mode: 0o750 });
+      const tmp = `${full}.${randomBytes(6).toString("hex")}.tmp`;
+      await writeFile(tmp, data, { mode: 0o640 });
+      await rename(tmp, full);
+    },
+    async get(key) {
+      try {
+        return await readFile(resolve(key));
+      } catch (error) {
+        if ((error as NodeJS.ErrnoException).code === "ENOENT") return null;
+        throw error;
+      }
+    },
+    async delete(key) {
+      await rm(resolve(key), { force: true });
+    },
+  };
+}