feat: initial Transmute app — universal client-side file converter

Full-stack client-side file converter with Next.js 15 static export.
Supports images (Canvas API), documents (mammoth/pdf-lib/jspdf),
audio/video (ffmpeg.wasm), and data formats (papaparse/yaml/xml).
Dark industrial UI with Space Grotesk + JetBrains Mono, animated
drop zone, glassmorphism file cards, progress rings, and ZIP downloads.
Zero server dependencies — files never leave the browser.

src/types/index.ts

@@ -0,0 +1,53 @@
+export type FileCategory = 'image' | 'document' | 'audio' | 'video' | 'data' | 'unknown';
+
+export type ConversionStatus = 'idle' | 'converting' | 'done' | 'error';
+
+export interface UploadedFile {
+  id: string;
+  file: File;
+  name: string;
+  size: number;
+  type: string;
+  category: FileCategory;
+  extension: string;
+  preview?: string;
+  targetFormat: string | null;
+  availableFormats: string[];
+  status: ConversionStatus;
+  progress: number;
+  convertedBlob?: Blob;
+  convertedName?: string;
+  error?: string;
+}
+
+export interface ConversionResult {
+  blob: Blob;
+  filename: string;
+}
+
+export const CATEGORY_COLORS: Record<FileCategory, string> = {
+  image: '#10b981',
+  document: '#0ea5e9',
+  audio: '#8b5cf6',
+  video: '#f43f5e',
+  data: '#f59e0b',
+  unknown: '#6b7280',
+};
+
+export const CATEGORY_ICONS: Record<FileCategory, string> = {
+  image: '\u{1F5BC}',
+  document: '\u{1F4C4}',
+  audio: '\u{1F3B5}',
+  video: '\u{1F3AC}',
+  data: '\u{1F4CA}',
+  unknown: '\u{1F4C1}',
+};
+
+export const CATEGORY_LABELS: Record<FileCategory, string> = {
+  image: 'Image',
+  document: 'Document',
+  audio: 'Audio',
+  video: 'Video',
+  data: 'Data',
+  unknown: 'File',
+};