feat(machine): seed + bunker-binding IPC bridge

get-atm-secrets now returns { spireSeed, bunkerBinding } instead of the raw
nsec (one-shot semantics kept). Adds IPC handlers + preload bindings for
saveBunkerBinding / clearBunkerBinding / resetBootstrapGate so the renderer
can persist a pairing and re-arm the cassette-state hello on re-pair (#56).
resetBootstrapGate added to state-store. Types mirrored in electron.d.ts.

Part of Phase C, aiolabs/bitspire#52.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

apps/machine/electron/main.ts

@@ -26,14 +26,19 @@ import {
   getLastKnownConfigCreatedAt,
   getBootstrapPublishedAt,
   markBootstrapPublished,
+  resetBootstrapGate,
   applyOperatorCassettesConfig,
   getFeeConfig,
   getLastKnownFeeConfigCreatedAt,
   applyFeeConfig,
+  getBunkerBinding,
+  saveBunkerBinding,
+  clearBunkerBinding,
   type OperatorCassettesPayload,
   type FeeConfigPayload,
   type FeeConfigRow,
   type ApplyResult,
+  type StoredBunkerBinding,
 } from './state-store.js'
 import { initializeHal, type HalInstance } from './hal-service.js'
 
@@ -323,14 +328,31 @@ let secretsConsumed = false
 ipcMain.handle('get-atm-secrets', () => {
   if (secretsConsumed) {
     console.warn('[Electron] SECURITY: get-atm-secrets called after secrets already consumed')
-    return { atmPrivateKey: '' }
+    return { spireSeed: '', bunkerBinding: null }
   }
   secretsConsumed = true
+  // The spire pairing seed (one-shot connect token inside) + the persisted
+  // bunker binding (transport key). The renderer resolves these into a
+  // BunkerSigner; see services/signer-resolver.ts (aiolabs/bitspire#52).
   return {
-    atmPrivateKey: process.env.VITE_ATM_PRIVATE_KEY || '',
+    spireSeed: process.env.VITE_SPIRE_SEED || '',
+    bunkerBinding: getBunkerBinding(),
   }
 })
 
+// Bunker binding persistence — the renderer writes the binding after a
+// successful pairing (connectNewSeed), and resets the bootstrap gate so the
+// new operator receives the spire's hello-event (aiolabs/bitspire#52 / #56).
+ipcMain.handle('state:save-bunker-binding', (_event, binding: StoredBunkerBinding): void => {
+  saveBunkerBinding(binding)
+})
+ipcMain.handle('state:clear-bunker-binding', (): void => {
+  clearBunkerBinding()
+})
+ipcMain.handle('state:reset-bootstrap-gate', (): void => {
+  resetBootstrapGate()
+})
+
 // State persistence IPC handlers
 ipcMain.handle('state:load-cassettes', () => loadCassettes())
 ipcMain.handle('state:set-cassettes', (_event, cassettes) => setCassettes(cassettes))

apps/machine/electron/preload.ts

@@ -42,13 +42,25 @@ export interface BrandingConfig {
   logoDarkDataUrl: string | null
 }
 
+/**
+ * Persisted NIP-46 bunker binding (mirror of state-store's StoredBunkerBinding).
+ */
+export interface BunkerBindingRecord {
+  clientSecretHex: string
+  spirePubkey: string
+  bunkerUrl: string
+  seedFingerprint: string
+  pairedAt: number
+}
+
 /**
  * ATM secrets — returned once by getAtmSecrets(), then empty on subsequent calls.
+ * The spire pairing seed (carries the one-shot connect token) plus the persisted
+ * bunker binding; the renderer resolves these into a signer.
  */
 export interface AtmSecrets {
-  atmPrivateKey: string
-  /** Legacy LP admin token — retained until 3d removes the LP backend. */
-  adminToken?: string
+  spireSeed: string
+  bunkerBinding: BunkerBindingRecord | null
 }
 
 // Expose protected methods to renderer
@@ -100,6 +112,13 @@ contextBridge.exposeInMainWorld('electronAPI', {
     ipcRenderer.invoke('state:get-bootstrap-published-at'),
   markBootstrapPublished: (unixTimestamp: number): Promise<void> =>
     ipcRenderer.invoke('state:mark-bootstrap-published', unixTimestamp),
+
+  // Bunker binding persistence (aiolabs/bitspire#52)
+  saveBunkerBinding: (binding: BunkerBindingRecord): Promise<void> =>
+    ipcRenderer.invoke('state:save-bunker-binding', binding),
+  clearBunkerBinding: (): Promise<void> => ipcRenderer.invoke('state:clear-bunker-binding'),
+  resetBootstrapGate: (): Promise<void> => ipcRenderer.invoke('state:reset-bootstrap-gate'),
+
   applyOperatorCassettesConfig: (
     payload: {
       positions: Record<string, { denomination: number; count: number }>
@@ -212,6 +231,9 @@ declare global {
       getLastKnownConfigCreatedAt: () => Promise<number>
       getBootstrapPublishedAt: () => Promise<number | null>
       markBootstrapPublished: (unixTimestamp: number) => Promise<void>
+      saveBunkerBinding: (binding: BunkerBindingRecord) => Promise<void>
+      clearBunkerBinding: () => Promise<void>
+      resetBootstrapGate: () => Promise<void>
       applyOperatorCassettesConfig: (
         payload: { positions: Record<string, { denomination: number; count: number }> },
         eventCreatedAt: number

apps/machine/electron/state-store.ts

@@ -483,6 +483,16 @@ export function clearBunkerBinding(): void {
   db.prepare('DELETE FROM bunker_binding WHERE id = 1').run()
 }
 
+/**
+ * Reset the bootstrap-publish gate so the ATM re-publishes its
+ * `bitspire-cassettes-state` hello-event. Called on a re-pair (new seed) so
+ * the new operator receives the spire's current state (aiolabs/bitspire#56).
+ */
+export function resetBootstrapGate(): void {
+  if (!db) throw new Error('Database not initialized')
+  db.prepare('UPDATE meta SET value = ? WHERE key = ?').run('', 'bootstrapPublishedAt')
+}
+
 export type OperatorCassettesPayload = {
   positions: Record<string, { denomination: number; count: number }>
 }

apps/machine/src/types/electron.d.ts

@@ -39,10 +39,20 @@ export interface BrandingConfig {
   logoDarkDataUrl: string | null
 }
 
+/** Persisted NIP-46 bunker binding (mirror of state-store's StoredBunkerBinding). */
+export interface BunkerBindingRecord {
+  clientSecretHex: string
+  spirePubkey: string
+  bunkerUrl: string
+  seedFingerprint: string
+  pairedAt: number
+}
+
 export interface AtmSecrets {
-  atmPrivateKey: string
-  /** Legacy LP admin token — retained until 3d removes the LP backend. */
-  adminToken?: string
+  /** Spire pairing seed URL (`spire-seed:v1:…`); carries the one-shot connect token. */
+  spireSeed: string
+  /** Persisted bunker binding, or null when the ATM is unpaired. */
+  bunkerBinding: BunkerBindingRecord | null
 }
 
 declare global {
@@ -85,6 +95,9 @@ declare global {
       getLastKnownConfigCreatedAt: () => Promise<number>
       getBootstrapPublishedAt: () => Promise<number | null>
       markBootstrapPublished: (unixTimestamp: number) => Promise<void>
+      saveBunkerBinding: (binding: BunkerBindingRecord) => Promise<void>
+      clearBunkerBinding: () => Promise<void>
+      resetBootstrapGate: () => Promise<void>
       applyOperatorCassettesConfig: (
         payload: { positions: Record<string, { denomination: number; count: number }> },
         eventCreatedAt: number