fix(phys): A6.P7 — retail-binary cyl-vs-BSP dispatch (HAS_PHYSICS_BSP_PS gate)

Closes the door-cyl phantom slide where a sphere approaching a closed
cottage door at NE/SE headings could be blocked by the cyl's radial
normal contaminating the slide tangent into the slab face (live
evidence in door-a6p6-v2.utf8.log: 12 resolves with
cn=(0.86,0.51,0) attributed to door entity 0x000F4245).

Retail anchor: CPhysicsObj::FindObjCollisions at
acclient_2013_pseudo_c.txt:276861 dispatches BINARILY between
BSP-only and cyl+sphere based on HAS_PHYSICS_BSP_PS (0x10000 in
acclient.h:2833). For non-PvP, non-missile movers — every M1.5
scope walking-vs-static scenario — an entity with the flag set
tests its BSP exclusively; the foot cyl is never tested. ACE
confirms the truth table at PhysicsObj.cs:412-450 (HasPhysicsBSP,
missileIgnore, exemption).

Our dispatcher iterated every ShadowEntry independently and tested
both the cyl AND the BSP for a closed door. Cyl was registered
first (FromSetup walk order), and its diagonal radial slide normal
"won" attribution at the early-return on first non-OK. Result was
out=in for tangential motion along the door face.

Changes (~15 LOC + 7 unit tests):
- PhysicsStateFlags.HasPhysicsBsp = 0x00010000 (PhysicsBody.cs)
- Transition.BspOnlyDispatch(uint state) static predicate
  (TransitionTypes.cs) — mirrors retail's branch with M1.5 scope
  defaults (ebp_1 and eax_12 treated as false; wire PvP / missile
  refinements when those scopes ship)
- Per-entry guard in FindObjCollisions cyl/sphere branch
  (TransitionTypes.cs:2433) — continue when BspOnlyDispatch fires,
  with [cyl-skip-bsp] diagnostic line gated on ProbeBuildingEnabled
- A6P7DispatchRulesTests (7 tests, all GREEN): flag value + 6
  parameterized predicate cases

Verification: 14-test keep-green list from the 2026-05-25 handoff
passes (5 BSPQueryTests.FindCollisions_Path5_*, 2 CellTransitTests.A6P5_*,
2 DoorCollisionApparatusTests.Apparatus_DeadCenter_*,
5 DoorBugTrajectoryReplayTests, 1
CellarUpTrajectoryReplayTests.LiveCompare_FirstCap_FixClosesCottageFloorCap).
Total: 20/20 pass including the new 7-test predicate suite.

The DocumentsBug test (Apparatus_Grounded_50cmOffCenter) fails
post-fix BUT was already failing pre-fix in the worktree baseline
(verified by stashing the fix and re-running — same failure mode:
sphere blocks at start with floor normal (0,0,1)). Not in the
keep-green list, so this is a known pre-existing condition; the
test's own header comment instructs flipping the assertion when
the fix lands.

Investigation:
docs/research/2026-05-25-a6-door-cyl-retail-dispatch-investigation.md

Needs visual verification at Holtburg cottage door (NE/SE approach
should now slide smoothly along the door face — zero [cyl-test]
log lines attributed to door entity, replaced by [cyl-skip-bsp]).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/AcDream.Core/Physics/PhysicsBody.cs

@@ -32,6 +32,19 @@ public enum PhysicsStateFlags : uint
     Gravity        = 0x00000400,  // bit 10 — apply downward gravity
     Hidden         = 0x00001000,
     /// <summary>
+    /// A6.P7 (2026-05-25): retail HAS_PHYSICS_BSP_PS bit
+    /// (acclient.h:2833). When set, the entity exposes a per-Setup
+    /// BSP collision mesh; retail's
+    /// <c>CPhysicsObj::FindObjCollisions</c> at
+    /// acclient_2013_pseudo_c.txt:276861 dispatches the entity's
+    /// collision queries to the BSP path EXCLUSIVELY for non-PvP,
+    /// non-missile movers — the foot cylinder and per-Setup spheres
+    /// are NEVER tested in this case. Closed cottage doors have
+    /// state 0x10008 (STATIC | REPORT_COLLISIONS | HAS_PHYSICS_BSP).
+    /// ACE name: <c>PhysicsState.HasPhysicsBSP</c>.
+    /// </summary>
+    HasPhysicsBsp  = 0x00010000,  // bit 16 — retail HAS_PHYSICS_BSP_PS
+    /// <summary>
     /// L.3a (2026-04-30): retail INELASTIC_PS bit (acclient.h:2834).
     /// When set, wall-collisions zero the velocity instead of reflecting.
     /// Used by spell projectiles and missiles that should embed/explode on