Fix achievements firing before first unpause in normal world

- Added _firstUnpauseInNormalWorld flag to require player unpause
- Added _tutorialComplete flag to track tutorial state separately
- Added _onGameUnpaused() handler listening to game-unpaused event
- Achievements now ONLY enable after:
  1. Tutorial completed/skipped
  2. Player is in normal world
  3. Player unpauses for the first time
- All tracking functions (trackTrade, trackJourney, etc.) now blocked
  until first unpause in normal world
- checkAchievements() and unlockAchievement() also blocked until unpause
- Prevents achievements from registering before receiving first mission

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

Author: G-Fourteen