feat: operator command channel via Nostr (manual dispense)

Add a Nostr-native operator command channel using Kind 21003 (CLINK
Manage) events. Operators listed in OPERATOR_PUBKEYS can send encrypted
commands to the machine.

Phase 1 implements manual dispense: operator sends a dispense command,
machine verifies sender, checks it's idle, performs a direct HAL
dispense (bypassing state machine), and records the transaction.

When ref_txid is provided, the referenced failed transaction is updated
to status 'remediated', closing the loop on dispense errors.

Changes:
- CLINK types: add 'machine' resource, MachineDispenseRequest type
- CLINK client: support operator pubkey list (string | string[])
- Runtime config: VITE_OPERATOR_PUBKEYS env var
- Schema v4→v5: manual_dispense type, remediated_by column
- Lightning services: wire onManagement callback
- ATM store: handleManagementCommand with idle check + remediation

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

apps/machine/electron/preload.ts

@@ -25,6 +25,7 @@ export interface RuntimeConfig {
   dispenserDevice?: string
   cassettes?: string
   allowMockFallback: boolean
+  operatorPubkeys: string
 }
 
 /**
@@ -54,8 +55,8 @@ contextBridge.exposeInMainWorld('electronAPI', {
   getCashbox: () => ipcRenderer.invoke('state:get-cashbox'),
   recordTransaction: (tx: {
     txid: string
-    type: 'cash_in' | 'cash_out'
-    status: 'complete' | 'dispense_error' | 'partial'
+    type: 'cash_in' | 'cash_out' | 'manual_dispense'
+    status: 'complete' | 'dispense_error' | 'partial' | 'remediated'
     fiatCents: number
     sats: number
     feeSats: number
@@ -74,6 +75,8 @@ contextBridge.exposeInMainWorld('electronAPI', {
     error?: string | null
   }) => ipcRenderer.invoke('state:record-transaction', tx),
   emptyCashbox: () => ipcRenderer.invoke('state:empty-cashbox'),
+  remediateTransaction: (txid: string, remediatedByTxid: string): Promise<boolean> =>
+    ipcRenderer.invoke('state:remediate-transaction', txid, remediatedByTxid),
 
   // HAL hardware (runs in main process, exposed via IPC)
   halInit: (config: any): Promise<{ success: boolean; error?: string }> =>
@@ -147,6 +150,7 @@ declare global {
         error?: string | null
       }) => Promise<void>
       emptyCashbox: () => Promise<void>
+      remediateTransaction: (txid: string, remediatedByTxid: string) => Promise<boolean>
       // HAL hardware IPC
       halInit: (config: any) => Promise<{ success: boolean; error?: string }>
       halDispense: (amounts: any) => Promise<any>