Coop lockout fix, holidays full list, !fx convert, lottery cleanup

- Co-op: when a run wipes or completes, clear the 99-sentinel combat
  lock for participants and pin combat_actions_used to maxCombatActions.
  Previously the lock only released on the next midnight reset, so
  members were stuck unable to combat for the rest of the day after
  their run ended.
- Holidays: !holidays now prints the full list. Previously it called
  the same featured-only formatter as TwinBee's morning auto-post,
  so users saw the same truncated message twice with a misleading
  "Use !holidays for the full list" hint that pointed at itself.
- Forex: add currency conversion. Auto-detects when the first arg is
  numeric (`!fx 1500 USD EUR`) and also accepts an explicit `convert`
  subcommand. Tolerant parsing: "to"/"into"/"in"/"=" filters, comma
  and k/m suffix support, and any of `1500 USD EUR`, `1500 USD/EUR`,
  `USD/EUR 1500` orderings. Includes parser + comma-formatter tests.
- Lottery: drop 2-match prize tier. At 1/16 odds × €25 it was +EV per
  ticket on its own and bled the community pot (~€775/wk recently),
  preventing jackpot rollover from accumulating. Removed from scoring,
  payout loops, draw announcement, !lottery odds, and !lottery history.
  Match2Winners DB column kept (history rows preserved); always written
  as 0 going forward.
- Lottery: shift week boundary so Sat/Sun return next Monday. Friday's
  23:59 draw used to leave players locked at their 100-ticket cap until
  next Monday rolled in; now the cap resets immediately after the draw.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

internal/plugin/coop_dungeon_db.go

@@ -177,6 +177,21 @@ func completeCoopRun(runID int, status string, reward int) error {
 // reset (which would otherwise zero them) and at bot startup. Combat stays
 // locked for the full duration of the run — players in a co-op cannot also
 // solo-grind dungeons or arena.
+// unlockCoopCombatActionsForRun clears the 99-sentinel lock on the given run's
+// members and pins combat_actions_used to the daily cap (= maxCombatActions),
+// so they can't squeeze in extra combat today but are not blocked into
+// tomorrow if the midnight reset is delayed. Called when a run ends (wipe or
+// complete). Idempotent.
+func unlockCoopCombatActionsForRun(runID int) error {
+	d := db.Get()
+	_, err := d.Exec(`UPDATE adventure_characters
+		SET combat_actions_used = ?
+		WHERE combat_actions_used > ?
+		  AND user_id IN (SELECT user_id FROM coop_dungeon_members WHERE run_id = ?)`,
+		maxCombatActions, maxCombatActions, runID)
+	return err
+}
+
 func lockCoopCombatActions() error {
 	d := db.Get()
 	_, err := d.Exec(`UPDATE adventure_characters