feat(pocket-base): allow return portal relocation

design/log.md

@@ -98,3 +98,10 @@ description: Chronological record of material decisions affecting the Spigot Bas
 - Added the persisted owner setting `/basesettings pocket mobs enable|disable`, contextual autocomplete, and status reporting.
 - Reapplied saved spawn flags when Pocket Base worlds load and restored the prior world setting when persistence fails.
 - Verified the feature with `./gradlew clean check jar`.
+
+## 2026-08-24 — Relocatable Pocket Base return portals
+
+- Allowed Pocket Base owners to activate a complete return portal frame with flint and steel anywhere inside their unlocked pocket boundary.
+- Persisted one active return portal location while retaining the generated portal as the default for existing Pocket Bases.
+- Made only the selected intact frame functional without removing old frame blocks, preserving the void-return safety fallback.
+- Verified the feature with `./gradlew clean check jar`.

design/user-stories/us-016-build-and-use-pocket-base-portals.md

@@ -21,7 +21,12 @@ As a **Pocket Base owner**, I want to connect my normal base to my Pocket Base w
 - [x] Any player can use an active entrance without a separate visitor setting, warm-up, or cooldown.
 - [x] Visitors can build, break blocks, open containers, and otherwise interact normally inside the Pocket Base.
 - [x] The generated return portal sends players safely to the owner's active entrance.
-- [x] Return travel falls back to the server spawn when the owner has no valid active entrance.
+- [x] Only the owner can activate a complete portal frame inside their own Pocket Base with flint and steel.
+- [x] Every required return-frame block must be within the owner's unlocked Pocket Base boundary.
+- [x] Each Pocket Base has at most one active return portal, and activating another valid frame moves the active return location without removing the old frame.
+- [x] Relocated return portals persist through restarts, while existing Pocket Bases use the generated portal as their default.
+- [x] Breaking the active return frame disables return travel through it.
+- [x] Return travel falls back to the server spawn when the owner has no valid normal-world entrance.
 - [x] Falling below Y -64 performs the same safe return without void damage.
 - [x] Players who disconnect inside a Pocket Base remain there when they reconnect.
 - [x] Moving the normal base deactivates its entrance while preserving the Pocket Base world and its contents.