fix: Change mission_hub exit options to use DONE instead of END

Fixes issue where choosing conversation exit options would show
"reached end of story" console message. All mission_hub exit points
now use:

  #end_conversation
  -> DONE

Instead of:

  #end_conversation
  -> END

This preserves conversation state at mission_hub while cleanly
ending the interaction without triggering ink's end-of-story behavior.

Updated hub files:
- chen_hub.ink
- netherton_hub.ink
- haxolottle_hub.ink

Recompiled all hub JSON files to reflect changes.

story_design/ink/chen_hub.ink

@@ -55,7 +55,7 @@ EXTERNAL equipment_status()             // LOCAL - Status of player's equipment
 // ===========================================
 // MISSION HUB - Central routing point
 // Routes to personal conversations or mission-related topics
-// Game returns here after #exit_conversation from personal talks
+// Game returns here after #end_conversation from personal talks
 // ===========================================
 
 === mission_hub ===
@@ -115,8 +115,8 @@ EXTERNAL equipment_status()             // LOCAL - Status of player's equipment
 // EXIT OPTIONS
 + {mission_phase() == "active" and npc_location() == "field_support"} [That's all I needed, thanks]
     Dr. Chen: Roger that. I'll keep monitoring your situation. Call if you need anything!
-    #exit_conversation
-    -> END
+    #end_conversation
+    -> DONE
 
 + [That's all for now, Chen]
     {
@@ -127,8 +127,8 @@ EXTERNAL equipment_status()             // LOCAL - Status of player's equipment
         - else:
             Dr. Chen: Okay. Good luck with the mission!
     }
-    #exit_conversation
-    -> END
+    #end_conversation
+    -> DONE
 
 // ===========================================
 // HELPER FUNCTION - Check for available personal topics

story_design/ink/haxolottle_hub.ink

@@ -56,7 +56,7 @@ EXTERNAL operational_stress_level()     // LOCAL - How stressed the current situ
 // ===========================================
 // MISSION HUB - Central routing point
 // Routes to personal conversations or mission-related topics
-// Game returns here after #exit_conversation from personal talks
+// Game returns here after #end_conversation from personal talks
 // ===========================================
 
 === mission_hub ===
@@ -131,8 +131,8 @@ EXTERNAL operational_stress_level()     // LOCAL - How stressed the current situ
 // EXIT OPTIONS
 + {mission_phase() == "active"} [That's all I needed. Thanks, Hax.]
     Haxolottle: Roger. I'm monitoring your situation. Call if you need anything. Stay safe out there.
-    #exit_conversation
-    -> END
+    #end_conversation
+    -> DONE
 
 + [That's all for now]
     {
@@ -143,8 +143,8 @@ EXTERNAL operational_stress_level()     // LOCAL - How stressed the current situ
         - else:
             Haxolottle: Okay. Talk later!
     }
-    #exit_conversation
-    -> END
+    #end_conversation
+    -> DONE
 
 // ===========================================
 // HELPER FUNCTION - Check for available personal topics
@@ -270,7 +270,7 @@ Haxolottle: I've got eyes on security feeds. I'll guide you around patrol patter
 Haxolottle: {player_name()}—*firm but caring*—you've got this. I'm with you every step. Move now.
 
 #emergency_extraction_active
--> END
+-> DONE
 
 === equipment_crisis_support ===
 // Dr. Chen joins the comms channel

story_design/ink/netherton_hub.ink

@@ -55,7 +55,7 @@ EXTERNAL mission_phase()                // LOCAL - Phase of current mission ("pr
 // ===========================================
 // MISSION HUB - Central routing point
 // Routes to personal conversations or mission-related topics
-// Game returns here after #exit_conversation from personal talks
+// Game returns here after #end_conversation from personal talks
 // ===========================================
 
 === mission_hub ===
@@ -106,8 +106,8 @@ EXTERNAL mission_phase()                // LOCAL - Phase of current mission ("pr
 // EXIT OPTIONS
 + {mission_phase() == "active"} [That's all I needed, Director]
     Netherton: Understood. Execute the mission. Report any developments.
-    #exit_conversation
-    -> END
+    #end_conversation
+    -> DONE
 
 + [That will be all, Director]
     {
@@ -118,8 +118,8 @@ EXTERNAL mission_phase()                // LOCAL - Phase of current mission ("pr
         - else:
             Netherton: Dismissed.
     }
-    #exit_conversation
-    -> END
+    #end_conversation
+    -> DONE
 
 // ===========================================
 // HELPER FUNCTION - Check for available personal topics