feat(machine): operator branding — local-file source (issue #47 V1)

Read /var/lib/bitspire/branding/{logo.png,branding.json} on startup and
apply across the renderer. branding.json may set title, theme (one of
the 6 built-ins or "custom"), and a custom_colors map (with optional
.dark overlay) — unset CSS vars fall back to gruvbox.

Wiring:
- electron/main.ts:loadBranding() reads + validates the JSON and
  base64-encodes logo.png; surfaced via the existing get-config IPC
- composables/useBranding.ts holds reactive logoUrl/title refs and a
  single setBranding() setter — the seam where #48's Nostr-event
  source will eventually overlay the local-file source
- composables/useTheme.ts:applyBrandingTheme() handles built-in theme
  swap and injects a <style#branding-custom-theme> block for custom
- IdleView binds :src/title; App.vue calls setBranding() before the
  maintenance screen renders so "Under Service" wears operator branding

Provisioning: new deploy/nixos/provision-branding.sh rsyncs a local dir
to /var/lib/bitspire/branding/ via sudo-on-the-far-side and restarts
bitspire.service. The existing provision-atm.sh stays focused on .env.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

apps/machine/electron/main.ts

@@ -60,6 +60,89 @@ function loadEnvFile() {
 
 loadEnvFile()
 
+// Branding loader — reads /var/lib/bitspire/branding/{logo.png,branding.json}
+// and surfaces them on get-config. Per issue #47: local-file is the V1
+// source; V2 will overlay a higher-priority Nostr-event source from
+// satmachineadmin (issue #48). Renderer applies via useBranding().
+type BrandingConfig = {
+  title: string | null
+  theme: string | null
+  customColors?: Record<string, string>
+  customColorsDark?: Record<string, string>
+  logoDataUrl: string | null
+}
+
+const VALID_THEMES = new Set([
+  'gruvbox',
+  'catppuccin',
+  'cyberpunk',
+  'dracula',
+  'nord',
+  'tokyo-night',
+  'custom',
+])
+
+function loadBranding(): BrandingConfig | null {
+  const brandingDir = path.join(
+    fs.existsSync('/var/lib/bitspire') ? '/var/lib/bitspire' : process.cwd(),
+    'branding'
+  )
+  if (!fs.existsSync(brandingDir)) return null
+
+  let title: string | null = null
+  let theme: string | null = null
+  let customColors: Record<string, string> | undefined
+  let customColorsDark: Record<string, string> | undefined
+  let logoDataUrl: string | null = null
+
+  const jsonPath = path.join(brandingDir, 'branding.json')
+  if (fs.existsSync(jsonPath)) {
+    try {
+      const raw = JSON.parse(fs.readFileSync(jsonPath, 'utf-8'))
+      if (typeof raw.title === 'string') title = raw.title
+      if (typeof raw.theme === 'string' && VALID_THEMES.has(raw.theme)) theme = raw.theme
+      if (raw.custom_colors && typeof raw.custom_colors === 'object') {
+        const { dark, ...flat } = raw.custom_colors as Record<string, unknown>
+        const colors = Object.fromEntries(
+          Object.entries(flat).filter(([, v]) => typeof v === 'string')
+        ) as Record<string, string>
+        if (Object.keys(colors).length > 0) customColors = colors
+        if (dark && typeof dark === 'object') {
+          const darkColors = Object.fromEntries(
+            Object.entries(dark as Record<string, unknown>).filter(
+              ([, v]) => typeof v === 'string'
+            )
+          ) as Record<string, string>
+          if (Object.keys(darkColors).length > 0) customColorsDark = darkColors
+        }
+      }
+    } catch (e) {
+      console.warn('[Electron] Failed to parse branding.json:', e)
+    }
+  }
+
+  const logoPath = path.join(brandingDir, 'logo.png')
+  if (fs.existsSync(logoPath)) {
+    try {
+      const buf = fs.readFileSync(logoPath)
+      logoDataUrl = `data:image/png;base64,${buf.toString('base64')}`
+    } catch (e) {
+      console.warn('[Electron] Failed to read logo.png:', e)
+    }
+  }
+
+  if (
+    title === null &&
+    theme === null &&
+    !customColors &&
+    !customColorsDark &&
+    logoDataUrl === null
+  ) {
+    return null
+  }
+  return { title, theme, customColors, customColorsDark, logoDataUrl }
+}
+
 // Determine if we're in development
 const isDev =
   process.env.ELECTRON_FORCE_PROD !== '1' &&
@@ -165,6 +248,7 @@ ipcMain.handle('watchdog:pong', () => {
   missedPongs = 0
 })
 
+// pragma: allowlist secret start
 /**
  * Get runtime configuration from environment variables
  * This allows configuration to be set at runtime (not baked in at build time)
@@ -172,6 +256,7 @@ ipcMain.handle('watchdog:pong', () => {
  * SECURITY: Secrets (private key, admin token) are NOT included here.
  * Use 'get-atm-secrets' for secrets — it's a one-shot handler.
  */
+// pragma: allowlist secret end
 ipcMain.handle('get-config', () => {
   return {
     // LNbits nostr-transport connection (public info only)
@@ -199,9 +284,13 @@ ipcMain.handle('get-config', () => {
     // Fee rates — accepts percentage (5.55) or decimal (0.0555), auto-detected
     cashInFeeRate: parseFee(process.env.VITE_CASH_IN_FEE || '0.0333'),
     cashOutFeeRate: parseFee(process.env.VITE_CASH_OUT_FEE || '0.0777'),
+
+    // Operator branding (logo/title/theme) — null when no override
+    branding: loadBranding(),
   }
 })
 
+// pragma: allowlist secret start
 /**
  * One-shot secrets handler.
  *
@@ -215,6 +304,7 @@ ipcMain.handle('get-config', () => {
  * TODO: Move signing/encryption to main process entirely (Phase 2)
  * so the private key never crosses the IPC boundary.
  */
+// pragma: allowlist secret end
 let secretsConsumed = false
 ipcMain.handle('get-atm-secrets', () => {
   if (secretsConsumed) {