I want to tidy up the Campaign Loader so it always reflects our core Dealer Pulse campaigns (end-of-term and bespoke), not the old demo ones.

Please do the following carefully:

1. Search the project for the strings:
   - "Service Lane to Showroom"
   - "Lost Sale Follow-Back"
   - "Service Lane to Showroom"
   Remove any old hard-coded demo campaign arrays or objects that create these campaigns in the frontend. We should not show those names anywhere in the UI.

2. Open app/templates/dashboard.html and find the <script> block at the bottom of the file.

3. At the very top of that <script> block (before any function definitions), add this constant:

  const DEMO_CAMPAIGNS = [
    {
      campaign_id: "demo_1296",
      name: "12-9-6 Payment Loyalty Sweep",
      type: "renewals",
      status: "live",
      starts_on: "2025-11-14",
      ends_on: null,
      target_segment: "Customers with 12, 9 or 6 payments remaining",
      notes: "Focus on a like-for-like or upgraded Audi with minimal change to monthly payment."
    },
    {
      campaign_id: "demo_eot_bespoke",
      name: "End-of-Term Bespoke Review",
      type: "renewals",
      status: "planned",
      starts_on: "2025-12-01",
      ends_on: null,
      target_segment: "Customers in the final year of their agreement (12–1 payments remaining)",
      notes: "Personalised end-of-term review based on how the customer uses the car, mileage and future plans."
    },
    {
      campaign_id: "demo_vip_event",
      name: "VIP Loyalty Event – Lincoln Audi",
      type: "renewals",
      status: "planned",
      starts_on: "2026-01-15",
      ends_on: "2026-01-31",
      target_segment: "Selected existing Audi drivers invited to a VIP event",
      notes: "In-person event with tailored offers, early access to stock and loyalty-focused finance support."
    }
  ];

4. Still in app/templates/dashboard.html, update the loadCampaigns() function so that it uses the real API data if present, but falls back to these DEMO_CAMPAIGNS when the API returns no rows.

   Specifically, inside loadCampaigns(), after we call fetch("/api/campaigns...") and parse the JSON, replace the existing lines that set the campaigns array with this:

      const payload = await res.json();
      let campaigns = payload.data || [];

      // If there are no campaigns in the database yet, fall back to our core Dealer Pulse demo campaigns
      if (!campaigns.length) {
        campaigns = DEMO_CAMPAIGNS;
      }

   Keep the rest of the logic in loadCampaigns() the same (the forEach that builds the cards, the live vs upcoming split, etc).

5. Make sure that after this change:
   - The Campaign Loader shows exactly these three campaigns when the API returns an empty array.
   - The filter controls (Status / Type) still work with the new demo campaigns.
   - If the database later returns real campaigns from /api/campaigns, those should override the demo list (i.e. the demo list is only used when payload.data is empty).

6. Run the app and confirm there are no JavaScript errors in the console, and that the Campaigns tab now shows:
   - "12-9-6 Payment Loyalty Sweep"
   - "End-of-Term Bespoke Review"
   - "VIP Loyalty Event – Lincoln Audi"
   as the only demo campaigns when the DB has no campaigns.