fix(pl24): demo-page retry in fetchP4Page + Volvo drill diagnostics

PL24 serves a stripped NOT_LOGGED_IN_DEMO page (no groups/parts) when the
service token is stale. decodeVinForService retries on this, but drill paths
(fetchSubGroupsByPath/fetchPartsByPath) reach upstream only via fetchP4Page,
which didn't — so Volvo subgroup drilling parsed empty demo pages. Retry once
with fresh auth on a demo page. Adds a Volvo-drill diagnostic log.

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

apps/api/src/integrations/pl24/pl24-ford-legacy.service.ts

@@ -161,6 +161,9 @@ export class PL24FordLegacyService {
           const lp = href.startsWith("/") ? href : `${basePath}/${href}`;
           subs.push({ id: href, code: href, name, linkPath: lp });
         }
+        this.logger.log(
+          `Volvo vin-group drill: htmlLen=${html.length} groupParamLinks=${(html.match(/group\d+=/g) || []).length} subs=${subs.length}${html.includes("NOT_LOGGED_IN_DEMO") ? " [DEMO]" : ""}`,
+        );
         if (subs.length > 0) {
           await this.redis.setJson(cacheKey, subs, 86400);
         }
@@ -3156,6 +3159,7 @@ export class PL24FordLegacyService {
     serviceName: string,
     isFullUrl = false,
     account: "tr" | "de" = "tr",
+    retried = false,
   ): Promise<string | null> {
     // Some catalogs (Volvo vin-group.action) store hrefs relative to the catalog
     // directory (e.g. "vin-group.action?group1=…"). Prefix the service basePath
@@ -3206,7 +3210,21 @@ export class PL24FordLegacyService {
         return JSON.stringify(json);
       }
 
-      return await response.text();
+      const html = await response.text();
+      // Demo mode: PL24 serves a stripped NOT_LOGGED_IN_DEMO page (no real
+      // groups/parts) when the service token is stale. decodeVinForService
+      // retries on this, but drill paths reach upstream only through here —
+      // so retry once with fresh auth before parsing an empty page.
+      if (!retried && html.includes("PL24_SUPPORT")) {
+        const support = this.extractScriptVariable<FordPL24Support>(html, "PL24_SUPPORT");
+        if (support?.demo || support?.role === "NOT_LOGGED_IN_DEMO") {
+          this.logger.warn(`Ford legacy: demo page for ${serviceName}, re-authing + retry`);
+          this.authService.clearTokensForAccount(account);
+          await this.authService.authorizeServiceForAccount(serviceName, account);
+          return this.fetchP4Page(url, serviceName, isFullUrl, account, true);
+        }
+      }
+      return html;
     } catch (error) {
       const err = error as Error;
       this.logger.error(