fix(physics): TransitionalInsert returns the real exhausted-retry state

Per the TS-4/#116 oracle plan (docs/research/2026-07-30-ts4-116-oracle-plan.md
§1.4, §4 item 1): TransitionalInsert's retry loop hardcoded
`return TransitionState.Slid;` when the attempt budget exhausted, despite
the comment's own claim of returning "whatever the last iteration said."
ACE's equivalent (Transition.cs:933, `return transitState;`) and retail's
(pc:273363, 0x0050b949, `return edi;`) both reuse one state variable
across the composite per-attempt call and return whatever it holds.

acdream's per-phase dispatch (env/building/object/other-cells/neg-poly/
step-down) is split across several locals instead of ACE's single
composite call, so `transitState` is now re-synced from whichever
phase-local variable most recently caused a retry `continue`, and the
final return uses that real value instead of the hardcoded constant.

Blast radius is zero: ValidateTransition's "not OK" branch treats
Collided/Adjusted/Slid identically, and every caller of TransitionalInsert
either feeds the result straight into ValidateTransition/
ValidatePlacementTransition (both `== OK` vs. not) or checks `== OK`
directly. Full AcDream.Core.Tests suite: 4059 passed / 2 skipped, no
change in pass count.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

src/AcDream.Core/Physics/TransitionTypes.cs

@@ -1700,7 +1700,12 @@ public sealed class Transition
         var ci = CollisionInfo;
         var oi = ObjectInfo;
 
-        TransitionState transitState;
+        // Initializer is unreachable in practice (numAttempts > 0 is
+        // guaranteed by the guard above, so the loop below always runs at
+        // least once and assigns transitState before any read) — required
+        // only to satisfy C#'s definite-assignment analysis, which can't
+        // connect the early-return guard to the loop bound.
+        TransitionState transitState = TransitionState.OK;
 
         for (int attempt = 0; attempt < numAttempts; attempt++)
         {
@@ -1742,6 +1747,7 @@ public sealed class Transition
 
             if (bldgState == TransitionState.Slid)
             {
+                transitState = bldgState;
                 ci.ContactPlaneValid = false;
                 ci.ContactPlaneIsWater = false;
                 sp.NegPolyHit = false;
@@ -1750,6 +1756,7 @@ public sealed class Transition
 
             if (bldgState == TransitionState.Adjusted)
             {
+                transitState = bldgState;
                 sp.NegPolyHit = false;
                 continue;
             }
@@ -1771,6 +1778,7 @@ public sealed class Transition
                 // Object collision applied a push-out and set sliding normal.
                 // Retry at the new CheckPos — we may have slid into another
                 // object, or need to re-verify env at the new position.
+                transitState = objState;
                 ci.ContactPlaneValid = false;
                 ci.ContactPlaneIsWater = false;
                 sp.NegPolyHit = false;
@@ -1781,6 +1789,7 @@ public sealed class Transition
             {
                 // Object modified CheckPos (e.g. PerfectClip adjust_to_plane).
                 // Retry at the new position.
+                transitState = objState;
                 sp.NegPolyHit = false;
                 continue;
             }
@@ -1805,7 +1814,10 @@ public sealed class Transition
                 return TransitionState.Collided;
 
             if (otherState != TransitionState.OK)
+            {
+                transitState = otherState;
                 continue;   // ADJUSTED / SLID → retry the attempt
+            }
 
             // ── Phase 3: both env and objects returned OK ──────────────
             // Handle Collide flag (BSP path 6 set it on a non-contact hit).
@@ -1943,6 +1955,7 @@ public sealed class Transition
                         var stepUpSlideRes = sp.StepUpSlide(this);
                         if (stepUpSlideRes == TransitionState.Slid)
                         {
+                            transitState = stepUpSlideRes;
                             ci.ContactPlaneValid = false;
                             ci.ContactPlaneIsWater = false;
                             continue;
@@ -1979,6 +1992,7 @@ public sealed class Transition
                         return TransitionState.Collided;   // degenerate slide → hard stop
                     // Slid / Adjusted / OK → re-test at the (slid) CheckPos, mirroring
                     // retail's insert-loop continuation after slide_sphere.
+                    transitState = slideRes;
                     continue;
                 }
             }
@@ -2070,6 +2084,7 @@ public sealed class Transition
                 var edgeState = EdgeSlideAfterStepDownFailed(engine, stepDownHeight, zVal);
                 if (edgeState == TransitionState.Slid)
                 {
+                    transitState = edgeState;
                     ci.ContactPlaneValid = false;
                     ci.ContactPlaneIsWater = false;
                     sp.NegPolyHit = false;
@@ -2078,6 +2093,7 @@ public sealed class Transition
 
                 if (edgeState == TransitionState.Adjusted)
                 {
+                    transitState = edgeState;
                     sp.NegPolyHit = false;
                     continue;
                 }
@@ -2088,9 +2104,30 @@ public sealed class Transition
             return TransitionState.OK;
         }
 
-        // Exhausted retry attempts — return whatever the last iteration said.
+        // Exhausted retry attempts — return the real last transition state.
-        // (Defaults to Slid in practice since that's the only case that retries.)
+        //
-        return TransitionState.Slid;
+        // TS-4/#116 oracle pass (Campaign P final physics slice,
+        // docs/research/2026-07-30-ts4-116-oracle-plan.md §1.4, §4 item 1):
+        // this was hardcoded to TransitionState.Slid despite the comment's
+        // own claim of returning "whatever the last iteration said" — a
+        // real, citable port-accuracy divergence from ACE's
+        // `return transitState;` (Transition.cs:933) and retail's
+        // `return edi;` (acclient_2013_pseudo_c.txt:273363, 0x0050b949),
+        // both of which reuse ONE state variable across the composite
+        // per-attempt call and return whatever it holds when the retry
+        // budget is exhausted. acdream's per-phase dispatch (env/building/
+        // object/other-cells/neg-poly/step-down) is split across several
+        // locals instead of ACE's single composite call, so `transitState`
+        // is explicitly re-synced from whichever phase-local variable most
+        // recently caused a retry `continue` (see the `transitState = ...`
+        // assignments immediately above each `continue` in this loop).
+        // Blast radius: zero. ValidateTransition's "not OK" branch
+        // (`transitionState != TransitionState.Invalid`) treats
+        // Collided/Adjusted/Slid identically — every caller of
+        // TransitionalInsert either feeds its result straight into
+        // ValidateTransition/ValidatePlacementTransition (both of which
+        // only branch on `== OK` vs. not) or only checks `== OK` directly.
+        return transitState;
     }
 
     private TransitionState EdgeSlideAfterStepDownFailed(