Disable PA on/off ramps; restore mainline to pre-ramp state

Three iterations of the Daikoku PA ramps never read as a real
interchange. Measured why, rather than tuning further:

  * the entry and exit decks INTERSECTED -- 2547 sample pairs within
    30 studs horizontally at <12 studs dY, worst case 0.5 studs apart
    at dY=0.0. On screen that is the bowtie tangle of white rails.
  * both real Daikoku ramps turn the SAME way (clockwise; the guide
    video says "right, right"). This build mirrored them into each
    other.
  * the real arc wraps OUTSIDE the lot and forms its north/east
    boundary. This build cut across the apron interior.

Gated behind BUILD_PA_RAMPS=false rather than deleted -- the radius
was already correct (470 studs vs an OSM-measured mean of 469) and
the merge lands tangent at 0.1-0.2 deg divergence. Both worth keeping.

Also removed two leftovers that would have outlived the ramps:

  * rampOpen punched holes in the mainline's outer parapet, railing
    and kill wall for ramps that no longer exist -- a barrier gap with
    a drop behind it. Sealed via RAMP_EDGE_OPENINGS=false. Verified:
    Barrier/EdgeRail/KillWall = 1646 each = 823 samples x 2 edges,
    0 road samples without a guard within 90 studs.
  * gore zebra hatching painted 1024 bars + 64 boundary lines marking
    a junction that is not there. Sealed via RAMP_GORE_MARKINGS=false.

Verified after a cache-busting fresh rebuild (Studio's require() cache
otherwise serves the previous map and reports a false pass):
  parts 22628 -> 15988
  all ramp part classes = 0
  Road = 823 (unchanged), spawn pad + PASpawn intact
  clip probe TRUSTWORTHY (control +11/-0), CLIPPING=0

Research and rebuild spec kept for when this is revisited:
reference/ramps/BUILD_SPEC.md, INDEX.md (10 CC-licensed Commons
photos), docs/daikoku-reference-spec.md (OSM circle fits).

tools/capture_flyover.py

@@ -0,0 +1,132 @@
+#!/usr/bin/env python3
+"""Eyes-on shots of the PA flyover ramps.
+
+Camera targets are QUERIED FROM THE LIVE GEOMETRY on every run, never
+hardcoded. The previous capture script pinned literal coordinates at the
+old defect sites; after the ramps were redesigned those coords pointed at
+empty air and the shots silently framed the wrong thing. Same class of bug
+as the hardcoded yFork=96 -- a constant that stops matching the model.
+
+Each shot names a part and an offset; the part's real position is looked up
+in Studio at capture time. If a named part is missing the shot is SKIPPED
+with a loud message rather than falling back to a stale guess.
+"""
+import shutil
+import sys
+import time
+
+sys.path.insert(0, "/tmp")
+import rbx  # noqa: E402
+
+OUT = "/home/jesse/roblox/tokyo-wangan-racing/tools/shots"
+
+# name, anchor part, camera offset from anchor, look-at offset from anchor, fov
+SHOTS = [
+    # The flyover itself, from the side -- the money shot: ramp over deck.
+    ("F1_flyover_side", "PAEntryRampCross_100", (300, 150, 300), (0, -20, 0), 55),
+    # Underneath the crossing, looking up: proves real clearance.
+    ("F2_flyover_under", "PAEntryRampCross_100", (140, -70, 140), (0, 10, 0), 75),
+    # The spiral descending into the PA apron.
+    ("F3_spiral_into_pa", "PAEntryRampTrunk_200", (340, 220, 340), (-120, -60, -120), 60),
+    # Exit ramp climbing out of the PA.
+    ("F4_exit_climb", "PAExitRampTrunk_200", (-340, 200, 300), (60, -40, 40), 60),
+    # Where the descent lands on the far carriageway.
+    ("F5_landing_merge", "PAEntryRampNear_200", (220, 130, 220), (0, -15, 0), 55),
+    # Wide establishing shot of the whole interchange.
+    ("F6_wide", "PAEntryRampCross_100", (900, 620, 900), (-250, -120, -250), 60),
+]
+
+POS_QUERY = """
+local ws=game:GetService("Workspace"); local map=ws:FindFirstChild("Map")
+if not map then return "NOMAP" end
+local want={}
+for _,n in ipairs({%s}) do want[n]=true end
+local found={}
+for _,d in ipairs(map:GetDescendants()) do
+  if d:IsA("BasePart") and want[d.Name] then
+    found[#found+1]=("%%s=%%.1f,%%.1f,%%.1f"):format(d.Name,d.Position.X,d.Position.Y,d.Position.Z)
+  end
+end
+return table.concat(found,"|")
+"""
+
+CAM = """
+local cam = workspace.CurrentCamera
+cam.CameraType = Enum.CameraType.Scriptable
+cam.FieldOfView = {fov}
+cam.CFrame = CFrame.lookAt(Vector3.new({px},{py},{pz}), Vector3.new({tx},{ty},{tz}))
+return "ok"
+"""
+
+
+def fetch_anchors(names):
+    """Look up each anchor part's real position in the live datamodel."""
+    lst = ",".join('"%s"' % n for n in sorted(set(names)))
+    r = rbx.call(
+        "execute_luau",
+        {"datamodel_type": "Edit", "code": POS_QUERY % lst},
+        wait=40,
+        timeout=400,
+    )
+    txt = str(r)
+    out = {}
+    for chunk in txt.split("|"):
+        if "=" not in chunk:
+            continue
+        nm, _, vals = chunk.partition("=")
+        nm = nm.strip().strip("'\"[]{}() ")
+        parts = vals.strip().strip("'\"[]{}() ").split(",")
+        if len(parts) != 3:
+            continue
+        try:
+            out[nm] = tuple(float(v) for v in parts)
+        except ValueError:
+            continue
+    return out
+
+
+def main():
+    anchors = fetch_anchors([s[1] for s in SHOTS])
+    print(f"resolved {len(anchors)} anchors: {sorted(anchors)}")
+    made, skipped = [], []
+    for name, anchor, cam_off, look_off, fov in SHOTS:
+        if anchor not in anchors:
+            print(f"{name}: SKIP -- anchor {anchor} not found in model")
+            skipped.append(name)
+            continue
+        ax, ay, az = anchors[anchor]
+        px, py, pz = ax + cam_off[0], ay + cam_off[1], az + cam_off[2]
+        tx, ty, tz = ax + look_off[0], ay + look_off[1], az + look_off[2]
+        r = rbx.call(
+            "execute_luau",
+            {
+                "datamodel_type": "Edit",
+                "code": CAM.format(
+                    fov=fov, px=px, py=py, pz=pz, tx=tx, ty=ty, tz=tz
+                ),
+            },
+            wait=12,
+            timeout=300,
+        )
+        if isinstance(r, dict) and r.get("isError"):
+            print(f"{name}: CAM FAIL {str(r)[:120]}")
+            skipped.append(name)
+            continue
+        time.sleep(1.5)
+        cap = rbx.call(
+            "screen_capture", {"capture_id": "ScreenCapture_1"}, wait=22, timeout=300
+        )
+        imgs = cap.get("images") if isinstance(cap, dict) else None
+        if not imgs:
+            print(f"{name}: CAPTURE FAIL {str(cap)[:140]}")
+            skipped.append(name)
+            continue
+        dest = f"{OUT}/{name}.jpg"
+        shutil.copy(imgs[0], dest)
+        made.append(dest)
+        print(f"{name}: OK ({anchor} @ {ax:.0f},{ay:.0f},{az:.0f}) -> {dest}")
+    print(f"\nMADE {len(made)}  SKIPPED {len(skipped)} {skipped if skipped else ''}")
+
+
+if __name__ == "__main__":
+    main()