feat: per-source pause/stop controls for queue admin

Add operator pause/resume/stop/start for individual adapter sources,
persisted in queue_state. Pause freezes draining and retains jobs; stop
clears pending/backoff jobs and blocks re-enqueue until start. Wires admin
tRPC endpoints plus a clean two-row Actions layout in the queue admin page.

app/server/src/trpc/router.ts

@@ -1707,6 +1707,34 @@ const adminRouter = router({
       return { cleared };
     }),
 
+  queueSourcePause: adminProcedure
+    .input(z.object({ source: z.string().min(1) }))
+    .mutation(({ ctx, input }) => {
+      ctx.queue.pauseSource(input.source);
+      return { ok: true, source: input.source };
+    }),
+
+  queueSourceResume: adminProcedure
+    .input(z.object({ source: z.string().min(1) }))
+    .mutation(({ ctx, input }) => {
+      ctx.queue.resumeSource(input.source);
+      return { ok: true, source: input.source };
+    }),
+
+  queueSourceStop: adminProcedure
+    .input(z.object({ source: z.string().min(1) }))
+    .mutation(({ ctx, input }) => {
+      const cleared = ctx.queue.stopSource(input.source);
+      return { ok: true, source: input.source, cleared };
+    }),
+
+  queueSourceStart: adminProcedure
+    .input(z.object({ source: z.string().min(1) }))
+    .mutation(({ ctx, input }) => {
+      ctx.queue.startSource(input.source);
+      return { ok: true, source: input.source };
+    }),
+
   queueClearDone: adminProcedure
     .input(z.object({ olderThanHours: z.number().min(1).max(336).optional().default(24) }))
     .mutation(({ ctx, input }) => {