Add openFile support for opening files with system viewer

Added new filesystem handler for opening files with the system's default viewer:
- Implemented haextension.fs.openFile handler in filesystem.ts
- Writes files to temp directory and opens with openPath from opener plugin
- Added Tauri permissions: opener:allow-open-path with $TEMP/** scope
- Added filesystem permissions for temp directory access

This enables extensions to open files (like images) in the native system viewer where users can zoom and interact with them naturally.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

src/composables/handlers/filesystem.ts

@@ -1,5 +1,7 @@
 import { save } from '@tauri-apps/plugin-dialog'
 import { writeFile } from '@tauri-apps/plugin-fs'
+import { openPath } from '@tauri-apps/plugin-opener'
+import { tempDir, join } from '@tauri-apps/api/path'
 import type { IHaexHubExtension } from '~/types/haexhub'
 import type { ExtensionRequest } from './types'
 
@@ -42,6 +44,39 @@ export async function handleFilesystemMethodAsync(
       }
     }
 
+    case 'haextension.fs.openFile': {
+      const params = request.params as {
+        data: number[]
+        fileName: string
+        mimeType?: string
+      }
+
+      try {
+        // Convert number array back to Uint8Array
+        const data = new Uint8Array(params.data)
+
+        // Get temp directory and create file path
+        const tempDirPath = await tempDir()
+        const tempFilePath = await join(tempDirPath, params.fileName)
+
+        // Write file to temp directory
+        await writeFile(tempFilePath, data)
+
+        // Open file with system's default viewer
+        await openPath(tempFilePath)
+
+        return {
+          success: true,
+        }
+      }
+      catch (error) {
+        console.error('[Filesystem] Error opening file:', error)
+        return {
+          success: false,
+        }
+      }
+    }
+
     default:
       throw new Error(`Unknown filesystem method: ${request.method}`)
   }