feat(config): configure aura progression

design/log.md

@@ -19,3 +19,4 @@ description: Chronological record of material changes to the Spigot Creeper Fear
 - Extended US-001 so a self-destructing creeper awards deduplicated progress and normal feedback to every player its explosion hits.
 - Completed US-004 with an asynchronous self-service progress command, ordinary-player permission, completion output, and command metadata.
 - Completed US-005 with UUID-backed offline inspection, atomic progress and rank administration, separate permissions, online-state refresh, and audit logging.
+- Completed US-006 with validated per-rank requirements and multipliers, configurable feedback, persistent threshold administration, and safe reload behavior.

design/user-stories/us-006-configure-aura-progression.md

@@ -2,7 +2,7 @@
 type: User Story
 title: "US-006: Configure aura progression"
 description: Let administrators safely configure and persist per-rank requirements, multipliers, and feedback.
-status: backlog
+status: done
 ---
 
 # US-006: Configure aura progression
@@ -11,18 +11,18 @@ As a **server administrator**, I want to configure progression and aura behavior
 
 ## Acceptance criteria
 
-- [ ] Configuration provides documented defaults for the six per-rank kill requirements and six unlocked-rank damage multipliers.
-- [ ] Rank requirements are positive integers.
-- [ ] Damage multipliers are finite and non-negative.
-- [ ] Progress boss-bar duration and player-facing rank messages are configurable.
-- [ ] `/creeperaura threshold <rank> <points>` validates, applies, and persists the points required to unlock that rank.
-- [ ] `/creeperaura reload` safely loads externally edited configuration without requiring a server restart.
-- [ ] Threshold-management and reload commands require documented administrative permissions.
-- [ ] Invalid configuration is rejected with actionable diagnostics while the last valid configuration remains active.
-- [ ] Changing requirements never automatically removes an unlocked rank, grants a new rank, or discards current-tier progress.
-- [ ] After a requirement change, the player's next qualifying kill can grant at most the next rank when its requirement is satisfied.
-- [ ] Rank advancement resets current-tier progress to zero rather than carrying excess progress forward.
-- [ ] Configuration-command changes survive plugin and server restarts.
+- [x] Configuration provides documented defaults for the six per-rank kill requirements and six unlocked-rank damage multipliers.
+- [x] Rank requirements are positive integers.
+- [x] Damage multipliers are finite and non-negative.
+- [x] Progress boss-bar duration and player-facing rank messages are configurable.
+- [x] `/creeperaura threshold <rank> <points>` validates, applies, and persists the points required to unlock that rank.
+- [x] `/creeperaura reload` safely loads externally edited configuration without requiring a server restart.
+- [x] Threshold-management and reload commands require documented administrative permissions.
+- [x] Invalid configuration is rejected with actionable diagnostics while the last valid configuration remains active.
+- [x] Changing requirements never automatically removes an unlocked rank, grants a new rank, or discards current-tier progress.
+- [x] After a requirement change, the player's next qualifying kill can grant at most the next rank when its requirement is satisfied.
+- [x] Rank advancement resets current-tier progress to zero rather than carrying excess progress forward.
+- [x] Configuration-command changes survive plugin and server restarts.
 
 ## Related