app: Download button direct-downloads the update asset

app/electron/preload.ts

@@ -69,6 +69,7 @@ const bridge = {
     return () => { ipcRenderer.removeListener('codeburn:update', listener) }
   },
   platform: process.platform,
+  arch: process.arch,
 }
 
 contextBridge.exposeInMainWorld('codeburn', bridge)

app/renderer/components/AboutModal.tsx

@@ -3,7 +3,7 @@ import { useEffect, useState, type MouseEvent, type ReactNode } from 'react'
 import { version } from '../../package.json'
 import { FlameMark } from './FlameMark'
 import { BUILD_STAMP } from '../lib/build'
-import { releasePageUrl, useUpdateStatus } from '../hooks/useUpdateStatus'
+import { updateDownloadUrl, useUpdateStatus } from '../hooks/useUpdateStatus'
 import { codeburn } from '../lib/ipc'
 
 export type SocialLink = {
@@ -81,7 +81,7 @@ export function AboutModal({ socials, onClose }: { socials: SocialLink[]; onClos
                       <button
                         type="button"
                         className="set-text-button"
-                        onClick={() => { void codeburn.openExternal(releasePageUrl(status.tag!)) }}
+                        onClick={() => { void codeburn.openExternal(updateDownloadUrl(status.tag!)) }}
                       >
                         Download
                       </button>

app/renderer/components/UpdateBanner.tsx

@@ -1,6 +1,6 @@
 import { useState } from 'react'
 
-import { releasePageUrl, useUpdateStatus } from '../hooks/useUpdateStatus'
+import { updateDownloadUrl, useUpdateStatus } from '../hooks/useUpdateStatus'
 import { codeburn } from '../lib/ipc'
 
 const DISMISS_KEY = 'codeburn.updateDismissed'
@@ -32,7 +32,7 @@ export function UpdateBanner() {
     <div role="status" className="update-banner">
       <span>
         Update available: CodeBurn {status.latestVersion} ·{' '}
-        <button type="button" className="set-text-button" onClick={() => { void codeburn.openExternal(releasePageUrl(tag)) }}>Download</button>
+        <button type="button" className="set-text-button" onClick={() => { void codeburn.openExternal(updateDownloadUrl(tag)) }}>Download</button>
       </span>
       <button type="button" className="set-text-button" onClick={dismiss}>Dismiss</button>
     </div>

app/renderer/hooks/useUpdateStatus.test.ts

@@ -0,0 +1,44 @@
+import { describe, expect, it, vi } from 'vitest'
+
+vi.mock('../lib/ipc', () => ({
+  codeburn: { platform: 'linux', arch: 'x64' },
+}))
+
+import { directDownloadUrl, releasePageUrl, updateDownloadUrl } from './useUpdateStatus'
+
+const TAG = 'desktop-v0.9.19'
+const BASE = 'https://github.com/getagentseal/codeburn/releases/download/desktop-v0.9.19'
+
+describe('directDownloadUrl', () => {
+  it('maps macOS arm64 to the arm64 dmg', () => {
+    expect(directDownloadUrl(TAG, 'darwin', 'arm64')).toBe(`${BASE}/CodeBurn-0.9.19-arm64.dmg`)
+  })
+
+  it('maps macOS x64 to the plain dmg', () => {
+    expect(directDownloadUrl(TAG, 'darwin', 'x64')).toBe(`${BASE}/CodeBurn-0.9.19.dmg`)
+  })
+
+  it('maps Windows to the Setup exe regardless of arch', () => {
+    expect(directDownloadUrl(TAG, 'win32', 'x64')).toBe(`${BASE}/CodeBurn-Setup-0.9.19.exe`)
+    expect(directDownloadUrl(TAG, 'win32', undefined)).toBe(`${BASE}/CodeBurn-Setup-0.9.19.exe`)
+  })
+
+  it('returns null for Linux (three formats, the user picks on the page)', () => {
+    expect(directDownloadUrl(TAG, 'linux', 'x64')).toBeNull()
+  })
+
+  it('returns null for unknown platforms, missing mac arch, and foreign tags', () => {
+    expect(directDownloadUrl(TAG, 'freebsd', 'x64')).toBeNull()
+    expect(directDownloadUrl(TAG, 'darwin', undefined)).toBeNull()
+    expect(directDownloadUrl('mac-v0.9.19', 'darwin', 'arm64')).toBeNull()
+  })
+})
+
+describe('updateDownloadUrl fallback', () => {
+  it('falls back to the release page when no direct asset fits', () => {
+    // The mocked bridge reports linux, where no single asset fits, so the
+    // click target is the release page.
+    expect(releasePageUrl(TAG)).toBe('https://github.com/getagentseal/codeburn/releases/tag/desktop-v0.9.19')
+    expect(updateDownloadUrl(TAG)).toBe(releasePageUrl(TAG))
+  })
+})

app/renderer/hooks/useUpdateStatus.ts

@@ -23,8 +23,35 @@ export function useUpdateStatus(): UpdateStatus | null {
   return status
 }
 
-/** GitHub release page for a desktop tag — the Download target (no site #get
- *  anchor exists). https-only, so it passes the openExternal allowlist. */
+/** GitHub release page for a desktop tag — the fallback Download target when
+ *  no single direct asset fits (Linux ships three formats) or the platform is
+ *  unknown. https-only, so it passes the openExternal allowlist. */
 export function releasePageUrl(tag: string): string {
   return `https://github.com/getagentseal/codeburn/releases/tag/${tag}`
 }
+
+/**
+ * Direct asset download for the running platform, so Download saves the file
+ * instead of landing on a GitHub page. Filenames mirror the electron-builder
+ * output (app/DISTRIBUTION.md) and are version-derived from the tag. Returns
+ * null (callers fall back to the release page) for Linux — three formats, the
+ * user picks — and for unknown platforms or a preload without `arch`.
+ */
+export function directDownloadUrl(tag: string, platform: string | undefined, arch: string | undefined): string | null {
+  const version = tag.startsWith('desktop-v') ? tag.slice('desktop-v'.length) : null
+  if (!version) return null
+  let file: string | null = null
+  if (platform === 'darwin') {
+    if (!arch) return null
+    file = arch === 'arm64' ? `CodeBurn-${version}-arm64.dmg` : `CodeBurn-${version}.dmg`
+  } else if (platform === 'win32') {
+    file = `CodeBurn-Setup-${version}.exe`
+  }
+  if (!file) return null
+  return `https://github.com/getagentseal/codeburn/releases/download/${tag}/${file}`
+}
+
+/** The Download click target: direct asset when determinable, else the page. */
+export function updateDownloadUrl(tag: string): string {
+  return directDownloadUrl(tag, codeburn.platform, codeburn.arch) ?? releasePageUrl(tag)
+}

app/renderer/lib/types.ts

@@ -592,6 +592,9 @@ export interface CodeburnBridge {
   getPlans(period: Period): Promise<StatusJson>
   getActReport(): Promise<ActReportJson>
   readonly platform: string
+  /** Node process.arch of the host ('arm64', 'x64', ...). Absent on preloads
+   *  that predate the direct-download update link. */
+  readonly arch?: string
   getModels(period: Period, provider: string, byTask: boolean, range?: DateRange): Promise<ModelReportRow[]>
   getSessions(period: Period, provider: string, range?: DateRange): Promise<SessionRow[]>
   getCompareModels(period: Period, provider: string): Promise<ModelStats[]>

app/renderer/sections/Settings.tsx

@@ -8,7 +8,7 @@ import { Panel } from '../components/Panel'
 import { ProviderLogo } from '../components/ProviderLogo'
 import type { Section } from '../components/Sidebar'
 import { usePolled } from '../hooks/usePolled'
-import { releasePageUrl, useUpdateStatus } from '../hooks/useUpdateStatus'
+import { updateDownloadUrl, useUpdateStatus } from '../hooks/useUpdateStatus'
 import { version as appVersion } from '../../package.json'
 import { readDailyBudget } from '../lib/budget'
 import { formatConverted, formatUsd } from '../lib/format'
@@ -208,7 +208,7 @@ function GeneralPane({ period, refreshToken, claudeConfigs, claudeConfigSource,
         </div>
         <div className="about-sec set-last-sec">
           <div className="about-sec-h">About</div>
-          <div className="about-row"><span className="tx">Version {version}{updateNote && <small>{updateNote}</small>}</span><span className="r">{update?.updateAvailable && update.tag ? <button className="set-text-button" onClick={() => { void codeburn.openExternal(releasePageUrl(update.tag!)) }}>Download</button> : null}</span></div>
+          <div className="about-row"><span className="tx">Version {version}{updateNote && <small>{updateNote}</small>}</span><span className="r">{update?.updateAvailable && update.tag ? <button className="set-text-button" onClick={() => { void codeburn.openExternal(updateDownloadUrl(update.tag!)) }}>Download</button> : null}</span></div>
         </div>
       </div>
     </section>