feat: footer, auto-pause on no viewers, and Redsys question submissions

- Footer: add site-footer with one-liner + Cloud Host branding linking to cloudhost.es (mobile only, hidden on desktop)
- Auto-pause: game pauses automatically after AUTOPAUSE_DELAY_MS (default 60s) with no viewers connected; auto-resumes when first viewer connects; shows "Esperando espectadores…" in the UI
- Redsys: new /pregunta page lets viewers pay 1€ via Redsys to submit a fill-in question; submitted questions are used as prompts in the next round instead of AI generation; new redsys.ts implements HMAC_SHA256_V1 signing (3DES key derivation + HMAC-SHA256); notification endpoint at /api/redsys/notificacion handles server-to-server confirmation
- db.ts: questions table with createPendingQuestion / markQuestionPaid / getNextPendingQuestion / markQuestionUsed
- .env.sample: added AUTOPAUSE_DELAY_MS, PUBLIC_URL, REDSYS_* vars

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

game.ts

@@ -76,6 +76,7 @@ export type GameState = {
   viewerScores: Record<string, number>;
   done: boolean;
   isPaused: boolean;
+  autoPaused: boolean;
   generation: number;
 };
 
@@ -264,7 +265,7 @@ export async function callVote(
   return cleaned.startsWith("A") ? "A" : "B";
 }
 
-import { saveRound } from "./db.ts";
+import { saveRound, getNextPendingQuestion, markQuestionUsed } from "./db.ts";
 
 // ── Game loop ───────────────────────────────────────────────────────────────
 
@@ -325,12 +326,21 @@ export async function runGame(
 
     // ── Prompt phase ──
     try {
-      const prompt = await withRetry(
-        () => callGeneratePrompt(prompter),
-        (s) => isRealString(s, 10),
-        3,
-        `R${r}:prompt:${prompter.name}`,
-      );
+      // Use a user-submitted question if one is pending, otherwise call AI
+      const pendingQ = getNextPendingQuestion();
+      let prompt: string;
+      if (pendingQ) {
+        markQuestionUsed(pendingQ.id);
+        prompt = pendingQ.text;
+        log("INFO", `R${r}:prompt`, "Using user-submitted question", { id: pendingQ.id });
+      } else {
+        prompt = await withRetry(
+          () => callGeneratePrompt(prompter),
+          (s) => isRealString(s, 10),
+          3,
+          `R${r}:prompt:${prompter.name}`,
+        );
+      }
       if (state.generation !== roundGeneration) {
         continue;
       }