Route downloads into Documents\Video / Documents\Audio and simplify the home page

- Create Documents\Video and Documents\Audio on startup (ensureMediaDirs), and
  route each download into them by kind when no explicit output folder is set.
  An empty outputDir now means "sort by type"; a chosen folder still overrides
  for both kinds.
- Settings/Onboarding "Download folder" gains a placeholder + hint describing
  the blank = route-by-type behaviour.
- Trim the home download bar to the essentials: URL box, Search and Paste
  buttons, format/quality, and the Download button. Removed the private-mode
  toggle, per-download Options panel, custom-command panel, command preview, and
  the saving-to-folder line.
- Bump version to 0.3.0.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/main/download.ts

@@ -1,9 +1,9 @@
 import { spawn, execFile, type ChildProcess } from 'child_process'
 import { existsSync } from 'fs'
 import { join } from 'path'
-import { app, BrowserWindow, Notification, type WebContents } from 'electron'
+import { BrowserWindow, Notification, type WebContents } from 'electron'
 import { getYtdlpPath, getBinDir, getAria2cPath, getFfmpegPath, getFfprobePath } from './binaries'
-import { getSettings, getDownloadArchivePath } from './settings'
+import { getSettings, getDownloadArchivePath, getDefaultMediaDir } from './settings'
 import { getCookiesFilePath } from './cookies'
 import { listTemplates } from './templates'
 import { assertHttpUrl } from './url'
@@ -165,7 +165,11 @@ function resolveExtraArgs(opts: StartDownloadOptions, settings: Settings): strin
 /** Resolve settings + per-download overrides into the full yt-dlp argv. */
 export function buildCommand(opts: StartDownloadOptions): string[] {
   const settings = getSettings()
-  const outDir = opts.outputDir?.trim() || settings.outputDir || app.getPath('downloads')
+  // Output dir resolution: a per-download override wins, then the user's explicit
+  // global folder (Settings → Download folder), and finally — when both are blank —
+  // the per-kind default (Documents\Video for video, Documents\Audio for audio).
+  const outDir =
+    opts.outputDir?.trim() || settings.outputDir?.trim() || getDefaultMediaDir(opts.kind)
   // A collection (media-manager) download is filed into <channel>/<playlist>/
   // <NNN> - <title> folders; an ordinary download uses the flat filenameTemplate.
   const filenameTemplate = settings.filenameTemplate?.trim() || '%(title)s.%(ext)s'