First-run onboarding: contextual coach-marks + How-to-Play card + dev replay toggle

Teaches the deep, interlocking loop — especially the inverted win condition
(you win by CLEARING EXPEDITIONS, not by surviving base sieges; DR-042/DR-043).

- OnboardingSystem: client-only observe-only PresentationSystemGroup overlay
  (own UIDocument @ sortingOrder 60), soft-gated 10-beat coach-mark sequence
  with a world-space ▶ pointer; never mutates sim / never destroys a ghost.
- OnboardingStepMath: pure, unit-tested step machine (snapshot + IsSatisfied +
  scheme-aware prompts + pointer kinds + persisted-mask helpers).
- HowToPlayPanel: tabbed reference card (Controls / The Loop / Build / Threats /
  Win-Lose), reachable from the main menu and the pause overlay.
- Per-client client-local state in GameSettings (TutorialHints + OnboardingMask
  bitmask, additive) — a Join client keeps its own; a host save-wipe never
  re-teaches. Settings toggle + menu "Replay Tutorial".
- Dev "Force Each Launch" toggle (GameSettings.ForceOnboardingEachLaunch):
  SettingsService.Boot wipes the mask + forces hints on in-memory every launch
  so the tutorial always replays fresh.
- HudSystem suppresses its own location hint while onboarding is active
  (single prompt voice), via OnboardingState + [UpdateAfter(OnboardingSystem)].

Validated green: 20/20 EditMode; Play smoke confirmed overlay render, clean
U+25B6 pointer glyph, no system sort-cycle, and the force-wipe end-to-end.

Docs: DR-043 + session log; reusable lesson archived in the build-gotchas note.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Assets/_Project/Scripts/Client/UI/PauseMenuController.cs

@@ -16,6 +16,7 @@ namespace ProjectM.Client
         VisualElement _root;
         VisualElement _pausePanel;
         VisualElement _settingsPanel;
+        VisualElement _howToPanel;
         bool _open;
         /// <summary>True while the pause overlay is shown (BuildSendSystem suspends build-clicks while paused).</summary>
         public static bool Open;
@@ -49,6 +50,7 @@ namespace ProjectM.Client
             var card = MenuUi.Card("PAUSED");
             card.Add(MenuUi.Button("Resume", () => SetOpen(false)));
             card.Add(MenuUi.Button("Settings", ShowSettings));
+            card.Add(MenuUi.Button("How to Play", ShowHowToPlay));
             card.Add(MenuUi.Button("Quit to Menu", WorldLauncher.TeardownToMenu));
             card.Add(MenuUi.Button("Quit to Desktop", Quit));
             _pausePanel.Add(card);
@@ -61,6 +63,7 @@ namespace ProjectM.Client
             Open = open;
             if (_pausePanel != null) _pausePanel.style.display = open ? DisplayStyle.Flex : DisplayStyle.None;
             if (!open && _settingsPanel != null) { _settingsPanel.RemoveFromHierarchy(); _settingsPanel = null; }
+            if (!open && _howToPanel != null) { _howToPanel.RemoveFromHierarchy(); _howToPanel = null; }
             if (open) { UnityEngine.Cursor.lockState = CursorLockMode.None; UnityEngine.Cursor.visible = true; }
         }
 
@@ -75,6 +78,17 @@ namespace ProjectM.Client
             _root.Add(_settingsPanel);
         }
 
+        void ShowHowToPlay()
+        {
+            _pausePanel.style.display = DisplayStyle.None;
+            _howToPanel = HowToPlayPanel.Build(() =>
+            {
+                if (_howToPanel != null) { _howToPanel.RemoveFromHierarchy(); _howToPanel = null; }
+                _pausePanel.style.display = DisplayStyle.Flex;
+            });
+            _root.Add(_howToPanel);
+        }
+
         static void Quit()
         {
 #if UNITY_EDITOR