feat(scheduling): persist notifications, batch notify flow, dedup protection

- Add tab_scheduling_notifications table with bootstrap via ensureSchedulingTables()
- Notify endpoint rewritten: dedup by (suggestion_id, candidate_plate), history list, PATCH /:id for execute/cancel lifecycle
- Batch notify endpoint returns success/skipped/failed counts
- Suggestions response now carries notificationId + notificationStatus per candidate (joined from active-notification map)
- UI: select mode with checkboxes, floating action bar, confirmation modal listing each swap; already-notified items are dimmed and skipped
- Detail view badges show sent/executed state, preventing duplicate notify

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

src/server/routes/scheduling/db-schema.ts

@@ -0,0 +1,34 @@
+import pool from '../../db.js';
+
+const CREATE_NOTIFICATIONS_TABLE = `
+CREATE TABLE IF NOT EXISTS tab_scheduling_notifications (
+  id BIGINT PRIMARY KEY AUTO_INCREMENT,
+  suggestion_id VARCHAR(128) NOT NULL,
+  current_plate VARCHAR(32) NOT NULL,
+  candidate_plate VARCHAR(32) NOT NULL,
+  operator_id VARCHAR(64),
+  operator_name VARCHAR(128),
+  status VARCHAR(16) NOT NULL DEFAULT 'sent',
+  created_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP,
+  updated_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
+  executed_at DATETIME NULL,
+  notes VARCHAR(500) NULL,
+  before_mileage INT NULL,
+  after_mileage INT NULL,
+  INDEX idx_suggestion_id (suggestion_id),
+  INDEX idx_current_plate (current_plate),
+  INDEX idx_candidate_plate (candidate_plate),
+  INDEX idx_status (status),
+  INDEX idx_created_at (created_at)
+) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COMMENT='智能调度通知/执行记录'
+`;
+
+export async function ensureSchedulingTables(): Promise<void> {
+  try {
+    await pool.query(CREATE_NOTIFICATIONS_TABLE);
+    console.log('[scheduling] notifications table ready');
+  } catch (e) {
+    console.error('[scheduling] failed to ensure tables:', e);
+    throw e;
+  }
+}