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/Onboarding/OnboardingState.cs

@@ -0,0 +1,20 @@
+using UnityEngine;
+
+namespace ProjectM.Client
+{
+    /// <summary>
+    /// Tiny static coordination bridge for the first-run onboarding overlay. <see cref="Active"/> is true while a
+    /// coach-mark step is on screen (set each frame by <see cref="OnboardingSystem"/>); <see cref="HudSystem"/>
+    /// reads it to suppress its own ad-hoc location/gate hint so the player ever sees a single prompt voice.
+    /// A presentation-layer static, so it is RESET on play-enter (the CLAUDE.md stale-static rule) to avoid a
+    /// stale flag surviving a fast-enter-playmode domain reload and leaving the HUD hint suppressed.
+    /// </summary>
+    public static class OnboardingState
+    {
+        /// <summary>True while the coach-mark sequence is the active prompt voice (a step is being shown).</summary>
+        public static bool Active;
+
+        [RuntimeInitializeOnLoadMethod(RuntimeInitializeLoadType.SubsystemRegistration)]
+        static void ResetOnPlayEnter() => Active = false;
+    }
+}