Tensura ReReroll

 Changelog

Added
- **Rebirth (trrebirth) integration for gacha bonuses.** Rebirth prestige levels now
  count exactly like reset-counter points in the starter gacha:
  - Each rebirth level adds one bonus reroll (controlled by the existing
    "Reset counter adds rerolls" toggle in `/rereroll editor`).
  - Rebirth levels also count toward bonus starting unique skills (controlled by
    Tensura's `resetCounterBonusUnique` gamerule, just like scroll resets).
  - Reason: trrebirth performs its rebirth reset by calling Tensura's
    `resetEverything` directly, which never increments the reset counter — so
    rebirthed players previously opened the gacha with no bonus at all.
  - Stacks with scroll resets (2 resets + 1 rebirth = 3 bonus points).
  - Fully optional: without trrebirth installed nothing changes.
  - New classes: `GachaStartManagerMixin`, `RebirthLevelBridge`.

### Fixed
- **Character/skill reset scroll crash (reset silently did nothing).** Tensura
  divides by the `resetPerSkillLock` gamerule (default **0**) in
  `TensuraPlayerStorage.limitLockedSkills`. Any player with a bonus skill lock
  (e.g. granted by trrebirth) crashed the server thread with
  `ArithmeticException: / by zero` every time a reset scroll was released —
  before the reset ran and before the gacha could open. New
  `TensuraPlayerStorageMixin` skips the division when the gamerule is 0 or less
  (rule ≤ 0 now simply means "resets grant no extra skill locks").
  Note: in survival, the scroll was still consumed on failed attempts.

## 1.0.0

- Initial release: replaces Tensura's first-login starter selector and reset-scroll
  reincarnation menu with a gacha start flow (race + unique skill rolls), with an
  in-game editor (`/rereroll editor`) for rerolls, roll speed, brand name and
  race/skill blacklists. Rolls from the trrebirth prestige pools when installed.