Support superpowers: award 20 pts for buzzing before (+) marker

[Copilot]

Adds support for the superpower mark (+), which precedes the power mark (*) in a tossup and is worth 20 points (vs. 15 for power, 10 for ten).

Scoring logic (quizbowl/TossupRoom.js)

• Added inSuperpower: false / superpowerValue: 20 to previousTossup initial state
• scoreTossup() now detects (+) position and applies three-tier scoring:
  • Before (+) → 20 pts (inSuperpower)
  • Between (+) and (*) → 15 pts (inPower)
  • After (*) → 10 pts

const inSuperpower = superpowerIndex !== -1 && superpowerIndex >= this.wordIndex;
const inPower = !inSuperpower && powerIndex !== -1 && powerIndex >= this.wordIndex;

• readTossup() treats (+) like (*): zero reading delay

Client-side

• TossupClient.updateQuestion(): (+) is suppressed from the rendered question display
• SoloTossupRoom.toggleCorrect(): handles inSuperpower when adjusting points on correct/incorrect toggle
• SoloTossupClient.endCurrentTossup(): uses inSuperpower/superpowerValue in the recorded pointValue

Original prompt

---

This section details on the original issue you should resolve

<issue_title>Support superpowers</issue_title>
<issue_description>This is signified by a (+) appearing in the tossup text, similar to a (*) appearing for powers, and is worth 20 points</issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes Support superpowers #214

---

✨ Let Copilot coding agent set things up for you — coding agent works faster and does higher quality work when set up for your repo.

[geoffrey-wu]

Still need to update stat records in db from 20 -> 15, and correctly display powers/superpowers in stat pages