Add MVP server travel flow

AGRARIAN_DEVELOPMENT_ROADMAP.md

@@ -704,7 +704,10 @@ Target deliverable: A small group can join a server, spawn into one biome, gathe
   script already exist, then added a reusable Ubuntu gameplay-server bootstrap
   script and standardized the MVP endpoint as `play.agrariangame.com` on
   `7777/udp`.
-- [ ] Add server travel flow.
+- [x] Add server travel flow. Added an allowlisted `AgrarianServerTravel
+  GroundZero` admin/dev command that routes through server authority and travels
+  to `/Game/Agrarian/Maps/L_GroundZeroTerrain_Test?listen` for repeatable MVP
+  listen-server and dedicated-server tests.
 - [x] Define server authority over streamed terrain tiles.
 - [x] Define server response when a client requests a missing tile.
 - [x] Add player join flow.

Docs/MultiplayerNetworkingDesign.md

@@ -138,6 +138,19 @@ MVP join flow:
 The first MVP does not need account services, matchmaking, or full character
 persistence. It does need a deterministic flow that can be tested repeatedly.
 
+## Server Travel Flow
+
+MVP server travel is intentionally allowlisted. The admin/dev command
+`AgrarianServerTravel GroundZero` routes through the server and resolves to:
+
+```text
+/Game/Agrarian/Maps/L_GroundZeroTerrain_Test?listen
+```
+
+This gives listen-server and dedicated-server tests one repeatable travel path
+without exposing arbitrary map URLs to clients. Future travel expansion should
+add explicit tile/session validation before allowing any new map or region.
+
 ## Spawn And Respawn
 
 Initial MVP spawn:

Docs/Ops/DedicatedServerBuildRunbook.md

@@ -78,6 +78,15 @@ First cloud/server launch target:
 ./AgrarianGameServer L_GroundZeroTerrain_Test?listen -log -port=7777
 ```
 
+In-game/admin MVP travel command:
+
+```text
+AgrarianServerTravel GroundZero
+```
+
+This command is allowlisted to the Ground Zero MVP map and should remain the
+only server travel path until tile/session validation is stronger.
+
 Systemd launch target created by the bootstrap script:
 
 ```bash

Scripts/verify_server_travel_flow.py

@@ -0,0 +1,75 @@
+#!/usr/bin/env python3
+"""Validate MVP server travel flow wiring."""
+
+from pathlib import Path
+import sys
+
+ROOT = Path(__file__).resolve().parents[1]
+
+
+def read(relative_path: str) -> str:
+    path = ROOT / relative_path
+    if not path.exists():
+        raise AssertionError(f"Missing required file: {relative_path}")
+    return path.read_text(encoding="utf-8")
+
+
+def require(content: str, needle: str, context: str) -> None:
+    if needle not in content:
+        raise AssertionError(f"Missing {needle!r} in {context}")
+
+
+def main() -> int:
+    errors: list[str] = []
+    checks = {
+        "Source/AgrarianGame/AgrarianGamePlayerController.h": [
+            "void AgrarianServerTravel(FName MapName);",
+            "void ServerAgrarianServerTravel(FName MapName);",
+        ],
+        "Source/AgrarianGame/AgrarianGamePlayerController.cpp": [
+            "GroundZeroServerTravelMapPath",
+            "ResolveAgrarianServerTravelMap",
+            "AgrarianServerTravel(FName MapName)",
+            "ServerAgrarianServerTravel_Implementation",
+            "HasAuthority()",
+            "AgrarianServerTravel GroundZero",
+            "World->ServerTravel(TravelURL, false, false)",
+            "/Game/Agrarian/Maps/L_GroundZeroTerrain_Test",
+            "?listen",
+        ],
+        "Docs/MultiplayerNetworkingDesign.md": [
+            "Server Travel Flow",
+            "AgrarianServerTravel GroundZero",
+            "/Game/Agrarian/Maps/L_GroundZeroTerrain_Test?listen",
+            "without exposing arbitrary map URLs",
+        ],
+        "Docs/Ops/DedicatedServerBuildRunbook.md": [
+            "AgrarianServerTravel GroundZero",
+            "allowlisted to the Ground Zero MVP map",
+        ],
+        "AGRARIAN_DEVELOPMENT_ROADMAP.md": [
+            "[x] Add server travel flow.",
+            "AgrarianServerTravel",
+            "/Game/Agrarian/Maps/L_GroundZeroTerrain_Test?listen",
+        ],
+    }
+
+    for relative_path, needles in checks.items():
+        try:
+            content = read(relative_path)
+            for needle in needles:
+                require(content, needle, relative_path)
+        except AssertionError as exc:
+            errors.append(str(exc))
+
+    if errors:
+        for error in errors:
+            print(f"ERROR: {error}", file=sys.stderr)
+        return 1
+
+    print("PASS: MVP server travel flow is wired and documented.")
+    return 0
+
+
+if __name__ == "__main__":
+    raise SystemExit(main())

Source/AgrarianGame/AgrarianGamePlayerController.cpp

@@ -22,6 +22,20 @@
 namespace
 {
 	const FVector GroundZeroDeveloperTravelHomeLocation(-22000.0f, -3500.0f, 1148.0f);
+	const TCHAR* GroundZeroServerTravelMapPath = TEXT("/Game/Agrarian/Maps/L_GroundZeroTerrain_Test");
+
+	bool ResolveAgrarianServerTravelMap(const FName MapName, FString& OutTravelMap)
+	{
+		if (MapName == NAME_None
+			|| MapName == TEXT("GroundZero")
+			|| MapName == TEXT("L_GroundZeroTerrain_Test"))
+		{
+			OutTravelMap = GroundZeroServerTravelMapPath;
+			return true;
+		}
+
+		return false;
+	}
 
 	bool ApplyAgrarianItemUseEffect(const FName ItemId, const int32 Quantity, UAgrarianSurvivalComponent* SurvivalComponent, FString& OutEffectSummary)
 	{
@@ -260,6 +274,11 @@ void AAgrarianGamePlayerController::AgrarianTravelHome()
 	ServerAgrarianTravel(GroundZeroDeveloperTravelHomeLocation);
 }
 
+void AAgrarianGamePlayerController::AgrarianServerTravel(FName MapName)
+{
+	ServerAgrarianServerTravel(MapName);
+}
+
 void AAgrarianGamePlayerController::ServerAgrarianGrantItem_Implementation(FName ItemId, int32 Quantity)
 {
 	AAgrarianGameCharacter* AgrarianCharacter = GetPawn<AAgrarianGameCharacter>();
@@ -521,3 +540,24 @@ void AAgrarianGamePlayerController::ServerAgrarianTravel_Implementation(FVector
 		ClientMessage(TEXT("Developer travel failed: invalid destination."));
 	}
 }
+
+void AAgrarianGamePlayerController::ServerAgrarianServerTravel_Implementation(FName MapName)
+{
+	UWorld* World = GetWorld();
+	if (!World || !HasAuthority())
+	{
+		ClientMessage(TEXT("Agrarian server travel failed: no authoritative world."));
+		return;
+	}
+
+	FString TravelMap;
+	if (!ResolveAgrarianServerTravelMap(MapName, TravelMap))
+	{
+		ClientMessage(TEXT("Usage: AgrarianServerTravel GroundZero"));
+		return;
+	}
+
+	const FString TravelURL = FString::Printf(TEXT("%s?listen"), *TravelMap);
+	ClientMessage(FString::Printf(TEXT("Agrarian server travel requested: %s"), *TravelURL));
+	World->ServerTravel(TravelURL, false, false);
+}

Source/AgrarianGame/AgrarianGamePlayerController.h

@@ -90,6 +90,9 @@ public:
 	UFUNCTION(Exec)
 	void AgrarianTravelHome();
 
+	UFUNCTION(Exec)
+	void AgrarianServerTravel(FName MapName);
+
 protected:
 	UFUNCTION(Server, Reliable)
 	void ServerAgrarianGrantItem(FName ItemId, int32 Quantity);
@@ -120,4 +123,7 @@ protected:
 
 	UFUNCTION(Server, Reliable)
 	void ServerAgrarianTravel(FVector Destination);
+
+	UFUNCTION(Server, Reliable)
+	void ServerAgrarianServerTravel(FName MapName);
 };