feat(economy): add /lottery - daily draw, weighted winner takes the pot

Buy tickets (200 coins each, max 100/draw); one winner is drawn daily at 21:00
Tallinn time weighted by ticket count and credited the whole pot. Coin-conserving
by design: each ticket's cost is deducted at purchase and the winner is minted
exactly the sum of all ticket spend - no shared pot record, so no cross-period
race. Ticket state lives per-user keyed by draw period (full scan only at draw
time and for the pot view).

- New lottery.py: TICKET_COST/MAX_TICKETS/DRAW_HOUR, pure period_for, and
  do_buy_ticket / get_lottery_state / do_lottery_draw. New lottery_tickets +
  lottery_period schema fields (period added to _TEXT_FIELDS).
- /lottery [kogus] command (view or buy) with full failure handling.
- Scheduled lottery_draw_daily loop in bot.py (both profiles; each draws its own
  collection), announcing to the optional LOTTERY_CHANNEL_ID (config + .env).

14 tests: period boundary, buy/accumulate/reset/caps/guards, pot state, draw
payout with coin conservation, and the more-tickets-wins-more weighting.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_013VbAVsrZuYesea99mPMmPT

commands/economy_extra_commands.py

@@ -5,6 +5,7 @@ import datetime
 import random
 import time
 from collections.abc import Awaitable, Callable, MutableSet
+from zoneinfo import ZoneInfo
 
 import discord
 from discord import app_commands
@@ -15,6 +16,8 @@ import strings as S
 
 from ._replies import reply_db_error
 
+_TALLINN = ZoneInfo("Europe/Tallinn")
+
 
 def register_economy_extra_commands(
     tree: app_commands.CommandTree,
@@ -554,6 +557,64 @@ def register_economy_extra_commands(
         )
         await interaction.response.send_message(embed=embed)
 
+    # -----------------------------------------------------------------------
+    # /lottery - daily draw, one weighted winner takes the pot
+    # -----------------------------------------------------------------------
+    @tree.command(name="lottery", description=S.CMD["lottery"])
+    @app_commands.describe(kogus=S.OPT["lottery_kogus"])
+    async def cmd_lottery(interaction: discord.Interaction, kogus: int | None = None):
+        period = economy.period_for(datetime.datetime.now(_TALLINN))
+
+        if kogus is None:
+            state = await economy.get_lottery_state(period, interaction.user.id)
+            embed = discord.Embed(
+                title=S.LOTTERY_UI["title"],
+                description=S.LOTTERY_UI["desc"].format(
+                    draw_time=f"{economy.DRAW_HOUR}:00", cost=coin(state["ticket_cost"])
+                ),
+                color=0xF4C430,
+            )
+            embed.add_field(name=S.LOTTERY_UI["f_pot"], value=coin(state["pot"]), inline=True)
+            embed.add_field(name=S.LOTTERY_UI["f_players"], value=str(state["participants"]), inline=True)
+            if state["your_tickets"]:
+                chance = round(state["your_tickets"] / state["total_tickets"] * 100, 1)
+                embed.add_field(
+                    name=S.LOTTERY_UI["f_your"],
+                    value=S.LOTTERY_UI["your_val"].format(tickets=state["your_tickets"], chance=chance),
+                    inline=False,
+                )
+            else:
+                embed.add_field(name=S.LOTTERY_UI["f_your"], value=S.LOTTERY_UI["your_none"], inline=False)
+            await interaction.response.send_message(embed=embed)
+            return
+
+        if kogus <= 0:
+            await interaction.response.send_message(S.ERR["positive_amount"], ephemeral=True)
+            return
+        res = await economy.do_buy_ticket(interaction.user.id, kogus, period)
+        if not res["ok"]:
+            if res["reason"] == "db_error":
+                await reply_db_error(interaction)
+            elif res["reason"] == "banned":
+                await interaction.response.send_message(S.MSG_BANNED, ephemeral=True)
+            elif res["reason"] == "max_tickets":
+                await interaction.response.send_message(
+                    S.LOTTERY_UI["max_tickets"].format(cap=res["cap"], held=res["held"]), ephemeral=True
+                )
+            elif res["reason"] == "insufficient":
+                await interaction.response.send_message(
+                    S.ERR["broke_need"].format(need=coin(res["need"])), ephemeral=True
+                )
+            else:
+                await interaction.response.send_message(S.ERR["invalid_amount"], ephemeral=True)
+            return
+        await interaction.response.send_message(
+            S.LOTTERY_UI["bought"].format(
+                count=res["bought"], cost=coin(res["cost"]),
+                tickets=res["tickets"], balance=coin(res["balance"]),
+            )
+        )
+
     class LeaderboardView(discord.ui.View):
         PER_PAGE = 10