initial: bootstrap from BukidBountyApp base

resources/js/composables/useFileBlobCache.js

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+import { ref } from 'vue';
+import { useOPFS } from './useOPFS.js';
+
+const blobCache = ref({});
+const opfs = useOPFS();
+
+export function useFileBlobCache() {
+    /**
+     * Get a blob URL for a given hash.
+     * Order: 1. Locally cached URL (blobCache), 2. Persistent storage (OPFS), 3. Server Fetch.
+     * 
+     * @param {string} hash 
+     * @returns {Promise<string|null>}
+     */
+    const getFile = async (hash) => {
+        if (!hash) return null;
+        
+        // 1. Check in local session cache
+        if (blobCache.value[hash]) {
+            return blobCache.value[hash];
+        }
+
+        // 2. Check in persistent OPFS storage
+        const opfsBlob = await opfs.loadFile(hash);
+        if (opfsBlob) {
+            const blobUrl = URL.createObjectURL(opfsBlob);
+            blobCache.value[hash] = blobUrl;
+            return blobUrl;
+        }
+
+        // 3. Last resort: fetch from server
+        try {
+            const url = `/RequestData/File/${hash}`;
+            const response = await fetch(url);
+            
+            if (!response.ok) {
+                throw new Error(`Failed to fetch file: ${response.statusText}`);
+            }
+
+            const blob = await response.blob();
+            
+            // Save to persistent OPFS storage for future use
+            await opfs.saveFile(hash, blob);
+            
+            const blobUrl = URL.createObjectURL(blob);
+            
+            // Store in local session cache
+            blobCache.value[hash] = blobUrl;
+            
+            return blobUrl;
+        } catch (error) {
+            console.error(`Error fetching file with hash ${hash}:`, error);
+            return null;
+        }
+    };
+
+    /**
+     * Pre-cache a list of hashes.
+     * 
+     * @param {string[]} hashes 
+     */
+    const preCacheFiles = async (hashes) => {
+        if (!hashes || !Array.isArray(hashes)) return;
+        
+        const promises = hashes.map(hash => getFile(hash));
+        await Promise.all(promises);
+    };
+
+    return {
+        getFile,
+        preCacheFiles,
+        blobCache
+    };
+}