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/index.ts

@@ -14,6 +14,7 @@ import { getSettings, setSettings } from './settings'
 import { listHistory, addHistory, removeHistory, clearHistory } from './history'
 import { setupPortableData } from './portable'
 import { safeOpenPath, safeShowInFolder } from './reveal'
+import { openCookieLoginWindow, getCookiesStatus, clearCookies } from './cookies'
 
 // Force software compositing (GPU acceleration off). On this dev machine's old GeForce
 // GT 625 — and plausibly on the old / locked-down public PCs this app targets —
@@ -121,6 +122,10 @@ function registerIpcHandlers(): void {
   ipcMain.handle(IpcChannels.historyAdd, (_e, entry: HistoryEntry) => addHistory(entry))
   ipcMain.handle(IpcChannels.historyRemove, (_e, id: string) => removeHistory(id))
   ipcMain.handle(IpcChannels.historyClear, () => clearHistory())
+
+  ipcMain.handle(IpcChannels.cookiesLogin, (_e, url: string) => openCookieLoginWindow(url))
+  ipcMain.handle(IpcChannels.cookiesStatus, () => getCookiesStatus())
+  ipcMain.handle(IpcChannels.cookiesClear, () => clearCookies())
 }
 
 app.whenReady().then(() => {