feat: operator command queue for local TUI dispense

Add operator_commands table and polling loop so the TUI (or other local
tools) can trigger manual dispenses by inserting a command row into
SQLite. The Electron main process polls every 2s, executes pending
commands via HAL, records the transaction, and updates the command
status with the result.

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

apps/machine/electron/state-store.ts

@@ -95,6 +95,15 @@ export function initDatabase(dbPath?: string): void {
       dispensed INTEGER NOT NULL DEFAULT 0,
       rejected INTEGER NOT NULL DEFAULT 0
     );
+
+    CREATE TABLE IF NOT EXISTS operator_commands (
+      id INTEGER PRIMARY KEY AUTOINCREMENT,
+      command TEXT NOT NULL,
+      status TEXT NOT NULL DEFAULT 'pending',
+      result TEXT,
+      created_at INTEGER NOT NULL,
+      completed_at INTEGER
+    );
   `)
 
   // Seed meta + cashbox if first run, or run migrations
@@ -170,8 +179,20 @@ export function initDatabase(dbPath?: string): void {
       DROP TABLE transactions;
       ALTER TABLE transactions_new RENAME TO transactions;
     `)
+    db.exec(`
+      CREATE TABLE IF NOT EXISTS operator_commands (
+        id INTEGER PRIMARY KEY AUTOINCREMENT,
+        command TEXT NOT NULL,
+        status TEXT NOT NULL DEFAULT 'pending',
+        result TEXT,
+        created_at INTEGER NOT NULL,
+        completed_at INTEGER
+      );
+    `)
     db.prepare('UPDATE meta SET value = ? WHERE key = ?').run('5', 'schema_version')
-    console.log('[StateStore] Migrated schema v4 → v5 (added manual_dispense type, remediated_by)')
+    console.log(
+      '[StateStore] Migrated schema v4 → v5 (added manual_dispense type, remediated_by, operator_commands)'
+    )
   }
 
   const cashboxRow = db.prepare('SELECT id FROM cashbox WHERE id = 1').get()
@@ -401,6 +422,56 @@ export function recordTransaction(tx: TransactionInput): void {
   console.log('[StateStore] Recorded transaction:', tx.txid, tx.type, `(${tx.status})`)
 }
 
+// ---------------------------------------------------------------------------
+// Operator Command Queue
+// ---------------------------------------------------------------------------
+
+export interface OperatorCommand {
+  id: number
+  command: string
+  status: string
+  created_at: number
+}
+
+/**
+ * Get the next pending operator command (FIFO).
+ */
+export function getPendingCommand(): OperatorCommand | null {
+  if (!db) throw new Error('Database not initialized')
+
+  const row = db
+    .prepare(
+      "SELECT id, command, status, created_at FROM operator_commands WHERE status = 'pending' ORDER BY id LIMIT 1"
+    )
+    .get() as { id: number; command: string; status: string; created_at: number } | undefined
+
+  return row ?? null
+}
+
+/**
+ * Mark a command as executing (prevents double-pickup).
+ */
+export function markCommandExecuting(id: number): void {
+  if (!db) throw new Error('Database not initialized')
+  db.prepare(
+    "UPDATE operator_commands SET status = 'executing' WHERE id = ? AND status = 'pending'"
+  ).run(id)
+}
+
+/**
+ * Complete a command with a result.
+ */
+export function completeCommand(id: number, result: string, error?: boolean): void {
+  if (!db) throw new Error('Database not initialized')
+  db.prepare(
+    'UPDATE operator_commands SET status = ?, result = ?, completed_at = ? WHERE id = ?'
+  ).run(error ? 'error' : 'complete', result, Date.now(), id)
+}
+
+// ---------------------------------------------------------------------------
+// Transaction Remediation
+// ---------------------------------------------------------------------------
+
 /**
  * Mark a failed transaction as remediated by a manual dispense.
  * Only updates transactions with status 'dispense_error' or 'partial'.