refactor(wand): clean GSD comments and translate to English

- Reduce javadocs to one-liners, remove REQ/plan/phase references

- No behavioural change

src/main/java/com/mythlane/gravityflip/wand/GravityFlipWandInteraction.java

@@ -32,7 +32,7 @@ public final class GravityFlipWandInteraction extends SimpleInstantInteraction {
     // Volatile: writer (setup thread) must publish safely to reader threads (interaction dispatch).
     private static volatile WandSelectionStore STORE;
 
-    /** Wire the selection store before any click can be processed. */
+    /** Wires the selection store before any click can be processed. */
     public static void bindStore(WandSelectionStore store) {
         STORE = store;
     }

src/main/java/com/mythlane/gravityflip/wand/WandSelectionStore.java

@@ -26,7 +26,7 @@ public final class WandSelectionStore {
 
     private final ConcurrentHashMap<UUID, Selection> byUuid = new ConcurrentHashMap<>();
 
-    /** Record the Primary-click corner for the given player. */
+    /** Records the Primary-click corner for the given player. */
     public void setPos1(UUID uuid, int x, int y, int z) {
         if (uuid == null) return;
         byUuid.compute(uuid, (k, prev) -> new Selection(
@@ -34,7 +34,7 @@ public final class WandSelectionStore {
                 prev != null ? prev.pos2 : null));
     }
 
-    /** Record the Secondary-click corner for the given player. */
+    /** Records the Secondary-click corner for the given player. */
     public void setPos2(UUID uuid, int x, int y, int z) {
         if (uuid == null) return;
         byUuid.compute(uuid, (k, prev) -> new Selection(
@@ -42,14 +42,14 @@ public final class WandSelectionStore {
                 new int[]{x, y, z}));
     }
 
-    /** Return the current selection for the given player (never null). */
+    /** Returns the current selection for the given player (never null). */
     public Selection get(UUID uuid) {
         if (uuid == null) return EMPTY;
         Selection s = byUuid.get(uuid);
         return s != null ? s : EMPTY;
     }
 
-    /** Forget the selection for the given player. */
+    /** Forgets the selection for the given player. */
     public void clear(UUID uuid) {
         if (uuid == null) return;
         byUuid.remove(uuid);