Add Phase B: cookies, aria2c, proxy/rate-limit, restrict-filenames & archive

Implements the remaining Phase B (Access & networking) items from
ROADMAP.md: cookie sources (browser cookie-store import, or a built-in
sign-in window that exports a Netscape cookie file via a persisted Electron
session partition), the aria2c external downloader, proxy/rate-limit,
restrict-filenames, and a download-archive to skip repeats.

Wires download.ts to the buildArgs() module added in the previous commit
(it wasn't hooked up yet) and renames its options param
NetworkOptions -> AccessOptions to reflect the wider scope now that cookies
and filename/archive flags joined proxy/rate-limit/aria2c.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/main/settings.ts

@@ -1,10 +1,12 @@
 import { app } from 'electron'
+import { join } from 'path'
 import Store from 'electron-store'
 import {
   AUDIO_FORMATS,
   VIDEO_CONTAINERS,
   VIDEO_CODECS,
   SPONSORBLOCK_CATEGORIES,
+  COOKIE_BROWSERS,
   DEFAULT_DOWNLOAD_OPTIONS,
   type Settings,
   type DownloadOptions,
@@ -20,7 +22,19 @@ const DEFAULTS: Settings = {
   filenameTemplate: '%(title)s.%(ext)s',
   theme: 'light',
   clipboardWatch: true,
-  downloadOptions: DEFAULT_DOWNLOAD_OPTIONS
+  downloadOptions: DEFAULT_DOWNLOAD_OPTIONS,
+  proxy: '',
+  rateLimit: '',
+  useAria2c: false,
+  cookieSource: 'none',
+  cookiesBrowser: 'chrome',
+  restrictFilenames: false,
+  downloadArchive: false
+}
+
+/** Fixed path for the --download-archive file; not user-configurable. */
+export function getDownloadArchivePath(): string {
+  return join(app.getPath('userData'), 'download-archive.txt')
 }
 
 // Coerce an untrusted partial into a valid DownloadOptions, falling back to the
@@ -98,7 +112,18 @@ export function setSettings(partial: Partial<Settings>): Settings {
         break
       }
       case 'clipboardWatch':
-        if (typeof value === 'boolean') s.set('clipboardWatch', value)
+      case 'useAria2c':
+      case 'restrictFilenames':
+      case 'downloadArchive':
+        if (typeof value === 'boolean') s.set(key, value)
+        break
+      case 'cookieSource':
+        if (value === 'none' || value === 'browser' || value === 'login') s.set(key, value)
+        break
+      case 'cookiesBrowser':
+        if ((COOKIE_BROWSERS as readonly string[]).includes(value as string)) {
+          s.set(key, value as Settings['cookiesBrowser'])
+        }
         break
       case 'downloadOptions':
         // Always store a fully-validated object; the renderer sends the whole
@@ -109,6 +134,8 @@ export function setSettings(partial: Partial<Settings>): Settings {
       case 'defaultVideoQuality':
       case 'defaultAudioQuality':
       case 'filenameTemplate':
+      case 'proxy':
+      case 'rateLimit':
         if (typeof value === 'string') s.set(key, value)
         break
     }