feat: TTL purge — purge_old_sessions + /purge command + startup hook

src/bot/bot.py

@@ -503,8 +503,70 @@ async def cmd_help(update: Update, ctx: ContextTypes.DEFAULT_TYPE):
 
 # ─── Bot setup ────────────────────────────────────────────────────────────────
 
+async def _purge_on_startup(app: Application) -> None:
+    db_conn = await get_db()
+    try:
+        db = ResearchDB(db_conn)
+        result = await db.purge_old_sessions(30)
+        if result["sessions"] > 0:
+            logger.info("Startup purge done", **result)
+    except Exception as e:
+        logger.warning("Startup purge failed — bot continues", error=str(e))
+    finally:
+        await db_conn.close()
+
+
+async def cmd_purge(update: Update, ctx: ContextTypes.DEFAULT_TYPE):
+    if not is_authorized(update.effective_user.id):
+        return
+
+    args = ctx.args or []
+
+    if not args:
+        days = 30
+    else:
+        try:
+            days = int(args[0])
+        except ValueError:
+            await update.message.reply_text(
+                "❌ Uso: `/purge [días]`", parse_mode=ParseMode.MARKDOWN
+            )
+            return
+        if days < 0:
+            await update.message.reply_text("❌ El número de días debe ser ≥ 0.")
+            return
+        if days == 0 and not (len(args) >= 2 and args[1] == "confirm"):
+            await update.message.reply_text(
+                "⚠️ Esto borrará *todas* las sesiones completadas.\n"
+                "Envía `/purge 0 confirm` para confirmar.",
+                parse_mode=ParseMode.MARKDOWN
+            )
+            return
+
+    db_conn = await get_db()
+    try:
+        db = ResearchDB(db_conn)
+        result = await db.purge_old_sessions(days)
+        await update.message.reply_text(
+            f"🗑️ Purged: {result['sessions']} sessions, "
+            f"{result['sources']} sources, "
+            f"{result['chunks']} chunks, "
+            f"{result['outputs']} outputs"
+        )
+    except Exception as e:
+        logger.error("Purge command failed", error=str(e))
+        await update.message.reply_text(f"❌ Purge failed: {str(e)[:200]}")
+    finally:
+        await db_conn.close()
+
+
 def create_bot() -> Application:
-    app = Application.builder().token(settings.telegram_bot_token).build()
+    app = (
+        Application.builder()
+        .token(settings.telegram_bot_token)
+        .post_init(_purge_on_startup)
+        .build()
+    )
 
     app.add_handler(CommandHandler("start", cmd_start))
     app.add_handler(CommandHandler("help", cmd_help))
@@ -516,6 +578,7 @@ def create_bot() -> Application:
     app.add_handler(CommandHandler("outputs", cmd_outputs))
     app.add_handler(CommandHandler("process", cmd_process))
     app.add_handler(CommandHandler("cancel", cmd_cancel))
+    app.add_handler(CommandHandler("purge", cmd_purge))
 
     return app