feat(base): implement progression system

design/user-stories/us-009-view-progression-and-notifications.md

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+---
+type: User Story
+title: "US-009: View progression and unlock notifications"
+description: Give players clear command, boss-bar, and full-screen feedback about their progression.
+status: in-progress
+---
+
+# US-009: View progression and unlock notifications
+
+As a **player**, I want to inspect my progression and receive timely milestone feedback so that I understand what I can unlock next.
+
+## Acceptance criteria
+
+- [ ] `/baseprogress` shows the player's Base, Base Size, Base Flight, Teleport Warm-up, and Teleport Cooldown paths.
+- [ ] Each path identifies earned levels, unmet prerequisites, current progress, the next threshold, and the next reward.
+- [ ] Locked secondary paths clearly identify Base I or another sequential level as their prerequisite.
+- [ ] Relevant qualifying activity briefly displays a configurable progress boss bar for the active milestone.
+- [ ] Boss-bar text and fill accurately represent the current count and threshold and never exceed 100 percent.
+- [ ] The automatic boss bar disappears after a configurable number of seconds.
+- [ ] `/baseprogress bossbar` toggles automatic progress boss bars on and off.
+- [ ] Disabling automatic boss bars does not prevent `/baseprogress` from displaying progress.
+- [ ] The boss-bar preference persists across reconnects and restarts.
+- [ ] Each newly unlocked level displays prominent full-screen title and subtitle text describing the reward.
+- [ ] Unlock notifications occur once per earned level and do not repeat after reconnecting or restarting.
+
+## Related
+
+- [US-001: Unlock and establish Base I](us-001-unlock-and-establish-base.md)
+- [US-004: Unlock and control base flight](us-004-unlock-and-control-base-flight.md)
+- [US-010: Administer player progression](us-010-administer-player-progression.md)