feat(core/slice-1): TeleportAnimSequencer — full 7-state Tick() with timed transitions and edge events

TunnelContinue exit gate: minMet requires worldReady (min-continue hold);
maxForce fires unconditionally at MaxContinue (safety-net fallback when
world never loads). This matches spec §3.4.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

tests/AcDream.Core.Tests/World/TeleportAnimSequencerTests.cs

@@ -68,4 +68,172 @@ public sealed class TeleportAnimSequencerTests
         var (_, events) = seq.Tick(dt: 0f, worldReady: false);
         Assert.Contains(TeleportAnimEvent.PlayEnterSound, events);
     }
+
+    // --- Task 1.3: State transitions — timing-correct Tick() ---
+
+    // Helper: drive the sequencer forward by total elapsed time using small fixed steps.
+    private static (TeleportAnimSnapshot snap, List<TeleportAnimEvent> allEvents)
+        DriveSeconds(TeleportAnimSequencer seq, float seconds, bool worldReady, float step = 0.016f)
+    {
+        var allEvts = new List<TeleportAnimEvent>();
+        float remaining = seconds;
+        TeleportAnimSnapshot last = default;
+        while (remaining > 0f)
+        {
+            float dt = Math.Min(step, remaining);
+            var (snap, evts) = seq.Tick(dt, worldReady);
+            last = snap;
+            allEvts.AddRange(evts);
+            remaining -= dt;
+        }
+        return (last, allEvts);
+    }
+
+    // --- Logout path: WorldFadeOut -> TunnelFadeIn -> Tunnel ---
+
+    [Fact]
+    public void Logout_AfterFadeTime_TransitionsToTunnelFadeIn()
+    {
+        var seq = new TeleportAnimSequencer();
+        seq.Begin(TeleportEntryKind.Logout);
+
+        // Consume the enter-sound tick at dt=0
+        seq.Tick(0f, worldReady: false);
+
+        // Drive just past FadeTime (1.0s)
+        DriveSeconds(seq, TeleportAnimSequencer.FadeTime + 0.02f, worldReady: false);
+
+        Assert.Equal(TeleportAnimState.TunnelFadeIn, seq.State);
+    }
+
+    [Fact]
+    public void Logout_After2xFadeTime_TransitionsToTunnel()
+    {
+        var seq = new TeleportAnimSequencer();
+        seq.Begin(TeleportEntryKind.Logout);
+        seq.Tick(0f, worldReady: false); // consume enter-sound
+
+        DriveSeconds(seq, 2f * TeleportAnimSequencer.FadeTime + 0.02f, worldReady: false);
+
+        Assert.Equal(TeleportAnimState.Tunnel, seq.State);
+    }
+
+    // --- Portal/Login/Death path: enters at Tunnel ---
+
+    [Fact]
+    public void Portal_StartsInTunnel_HoldsWhileNotReady()
+    {
+        var seq = new TeleportAnimSequencer();
+        seq.Begin(TeleportEntryKind.Portal);
+        seq.Tick(0f, worldReady: false); // consume enter-sound
+
+        // Drive 10s — should not advance past Tunnel while !worldReady
+        DriveSeconds(seq, 10f, worldReady: false);
+
+        Assert.Equal(TeleportAnimState.Tunnel, seq.State);
+    }
+
+    [Fact]
+    public void Portal_WhenWorldReady_TransitionsToTunnelContinue_EmitsEnterTunnelAndPlace()
+    {
+        var seq = new TeleportAnimSequencer();
+        seq.Begin(TeleportEntryKind.Portal);
+        seq.Tick(0f, worldReady: false); // consume enter-sound
+
+        // The very first tick with worldReady=true should advance Tunnel→TunnelContinue and emit Place.
+        var (_, evts) = seq.Tick(0.016f, worldReady: true);
+
+        Assert.Equal(TeleportAnimState.TunnelContinue, seq.State);
+        Assert.Contains(TeleportAnimEvent.Place, evts);
+    }
+
+    // --- TunnelContinue: MIN_CONTINUE hold then TunnelFadeOut ---
+
+    [Fact]
+    public void TunnelContinue_DoesNotAdvance_BeforeMinContinue()
+    {
+        var seq = new TeleportAnimSequencer();
+        seq.Begin(TeleportEntryKind.Portal);
+        seq.Tick(0f, worldReady: false);
+        // Enter TunnelContinue
+        seq.Tick(0.016f, worldReady: true);
+        Assert.Equal(TeleportAnimState.TunnelContinue, seq.State);
+
+        // Drive MinContinue - ε — should still be TunnelContinue
+        DriveSeconds(seq, TeleportAnimSequencer.MinContinue - 0.1f, worldReady: true);
+
+        Assert.Equal(TeleportAnimState.TunnelContinue, seq.State);
+    }
+
+    [Fact]
+    public void TunnelContinue_AdvancesToTunnelFadeOut_AfterMinContinue()
+    {
+        var seq = new TeleportAnimSequencer();
+        seq.Begin(TeleportEntryKind.Portal);
+        seq.Tick(0f, worldReady: false);
+        seq.Tick(0.016f, worldReady: true); // -> TunnelContinue
+
+        DriveSeconds(seq, TeleportAnimSequencer.MinContinue + 0.05f, worldReady: true);
+
+        Assert.Equal(TeleportAnimState.TunnelFadeOut, seq.State);
+    }
+
+    // --- MAX_CONTINUE forces progress even when !worldReady ---
+
+    [Fact]
+    public void TunnelContinue_ForcesAdvance_AtMaxContinue_EvenIfNotReady()
+    {
+        // Simulate: world never becomes fully ready but MAX_CONTINUE forces fade-out
+        // This path exercises the safety-net from spec §3.4.
+        var seq = new TeleportAnimSequencer();
+        seq.Begin(TeleportEntryKind.Portal);
+        seq.Tick(0f, worldReady: false);
+        // Manually push the state to TunnelContinue by passing worldReady=true for one tick,
+        // then simulate worldReady toggling back to false.
+        seq.Tick(0.016f, worldReady: true); // -> TunnelContinue
+
+        // Drive MaxContinue + ε with worldReady=false (simulating "world never loaded")
+        DriveSeconds(seq, TeleportAnimSequencer.MaxContinue + 0.05f, worldReady: false);
+
+        Assert.Equal(TeleportAnimState.TunnelFadeOut, seq.State);
+    }
+
+    // --- TunnelFadeOut -> WorldFadeIn: PlayExitSound edge event ---
+
+    [Fact]
+    public void TunnelFadeOut_EmitsPlayExitSound_OnTransitionToWorldFadeIn()
+    {
+        var seq = new TeleportAnimSequencer();
+        seq.Begin(TeleportEntryKind.Portal);
+        seq.Tick(0f, worldReady: false);
+        seq.Tick(0.016f, worldReady: true); // -> TunnelContinue
+
+        // Drive through MinContinue -> TunnelFadeOut
+        DriveSeconds(seq, TeleportAnimSequencer.MinContinue + 0.05f, worldReady: true);
+        Assert.Equal(TeleportAnimState.TunnelFadeOut, seq.State);
+
+        // Drive through FadeTime -> WorldFadeIn; PlayExitSound should fire on that edge
+        var (_, evts) = DriveSeconds(seq, TeleportAnimSequencer.FadeTime + 0.05f, worldReady: true);
+        Assert.Equal(TeleportAnimState.WorldFadeIn, seq.State);
+        Assert.Contains(TeleportAnimEvent.PlayExitSound, evts);
+    }
+
+    // --- WorldFadeIn -> Off: FireLoginComplete edge event ---
+
+    [Fact]
+    public void WorldFadeIn_EmitsFireLoginComplete_OnTransitionToOff()
+    {
+        var seq = new TeleportAnimSequencer();
+        seq.Begin(TeleportEntryKind.Portal);
+        seq.Tick(0f, worldReady: false);
+        seq.Tick(0.016f, worldReady: true); // -> TunnelContinue
+        DriveSeconds(seq, TeleportAnimSequencer.MinContinue + 0.05f, worldReady: true);
+        DriveSeconds(seq, TeleportAnimSequencer.FadeTime + 0.05f, worldReady: true); // -> WorldFadeIn
+
+        var (_, evts) = DriveSeconds(seq, TeleportAnimSequencer.FadeTime + 0.05f, worldReady: true);
+
+        Assert.Equal(TeleportAnimState.Off, seq.State);
+        Assert.False(seq.IsActive);
+        Assert.Contains(TeleportAnimEvent.FireLoginComplete, evts);
+    }
 }