Add client-side ZK and hotlink upload crypto with Pinia store.

Encrypt image bytes in the browser, keep keys out of POST bodies (URL fragment or path secret), and POST ciphertext via typed upload API helpers.

frontend/src/stores/upload.ts

@@ -0,0 +1,34 @@
+import { defineStore } from 'pinia';
+import { ALTCHA_REQUEST_HEADER } from '@/consts/altchaRequestHeader';
+import { api } from '@/plugins/axios';
+import type { CreateHotlinkUploadRequest } from '@/types/upload/CreateHotlinkUploadRequest';
+import type { CreateZkUploadRequest } from '@/types/upload/CreateZkUploadRequest';
+import type { CreatedUploadResult } from '@/types/upload/CreatedUploadResult';
+
+export const useUploadStore = defineStore('upload', () => {
+    const createZkUpload = async (body: CreateZkUploadRequest, altcha?: string): Promise<CreatedUploadResult> => {
+        const { data } = await api.post<CreatedUploadResult>('/uploads/zk', body, {
+            headers: getUploadRequestHeaders(altcha)
+        });
+
+        return data;
+    };
+
+    const createHotlinkUpload = async (
+        body: CreateHotlinkUploadRequest,
+        altcha?: string
+    ): Promise<CreatedUploadResult> => {
+        const { data } = await api.post<CreatedUploadResult>('/uploads/hotlink', body, {
+            headers: getUploadRequestHeaders(altcha)
+        });
+
+        return data;
+    };
+
+    const getUploadRequestHeaders = (altcha?: string) => (altcha ? { [ALTCHA_REQUEST_HEADER]: altcha } : undefined);
+
+    return {
+        createZkUpload,
+        createHotlinkUpload
+    };
+});