Run the title catch-up in its own YouTube lane

poc/src/media.ts

@@ -17,6 +17,8 @@ import {
     ScrapeEngine,
     ScrapeStore,
     scrapeDir,
+    TitleLane,
+    type TitleLaneStatus,
     snowflakeFromIso,
     resolveDbRoot,
     type MediaKind,
@@ -171,6 +173,7 @@ export class MediaService {
     private readonly rootDir = resolveDbRoot();
     private readonly engine: ScrapeEngine;
     private readonly backfill: BackfillQueue;
+    private readonly titles: TitleLane;
 
     private bot: BotClient | null = null;
     private botFetcher: SlopbotFetcher | null = null;
@@ -214,6 +217,14 @@ export class MediaService {
             log: line => this.deps.log?.(line)
         });
 
+        // The title catch-up lane talks to YouTube only, so it runs beside the backfill queue.
+        // It auto-starts because it is a one-time catch-up: with nothing pending it exits at once.
+        this.titles = new TitleLane(this.engine, {
+            rootDir: this.rootDir,
+            log: line => this.deps.log?.(line)
+        });
+        this.titles.start();
+
         const stale = this.engine.reconcileStaleJobs();
         if (stale.length) {
             this.deps.log?.(`paused ${stale.length} stale scrape(s) left running by a previous daemon`);
@@ -268,6 +279,20 @@ export class MediaService {
         };
     }
 
+    titleStatus(): TitleLaneStatus {
+        return this.titles.status();
+    }
+
+    startTitles(): TitleLaneStatus {
+        this.titles.start();
+        return this.titles.status();
+    }
+
+    pauseTitles(): TitleLaneStatus {
+        this.titles.pause();
+        return this.titles.status();
+    }
+
     startBackfill(chatId?: string): BackfillStatus {
         this.backfill.start(chatId);
         return this.backfillStatus();

poc/src/webui.ts

@@ -835,6 +835,27 @@ export function startWebUi(deps: WebUiDeps): WebUiHandle {
         })
     );
 
+    app.get(
+        "/api/media/titles",
+        wrap(async (_req, res) => {
+            res.json({ ok: true, result: deps.media.titleStatus() });
+        })
+    );
+
+    app.post(
+        "/api/media/titles/start",
+        wrap(async (_req, res) => {
+            res.json({ ok: true, result: deps.media.startTitles() });
+        })
+    );
+
+    app.post(
+        "/api/media/titles/pause",
+        wrap(async (_req, res) => {
+            res.json({ ok: true, result: deps.media.pauseTitles() });
+        })
+    );
+
     app.post(
         "/api/media/backfill/start",
         wrap(async (req, res) => {