Aux-lane suppression + PA geometry fixes; probe/verify tooling

MapBuilder.luau
  - Suppress the aux lane across samples 525-550 (AUX_SUPPRESS_FROM/TO),
    honoring the user's hand deletion in Studio so a rebuild no longer
    regenerates it.
  - Smoothstep the width ramp over AUX_BLEND=5 samples on each side. A hard
    cut produced a 26-stud lateral fence jog; the blend removes it.
  - DO NOT remove this suppression. Re-enabling it resurrects geometry the
    user deleted by hand.

rokit.toml
  - rojo 7.5.1 -> 7.7.0 to match the auto-updating Studio plugin.
    Server older than plugin fails the handshake with
    "attempt to index number with 'protocolVersion'".

tools/
  - 34 read-only probe/verify/capture scripts used to measure the datamodel
    instead of reasoning from source.

Verified-good baseline at this commit:
  total parts       16788
  PAWestSlip        60 segs, 34.4 deg total bend, worst 1.4, 0 kinks >5
  PAEastSlip        60 segs, 30.7 deg total bend, worst 1.3, 0 kinks >5
  AuxLane parts     30 (samples 525-550 deliberately absent)
  barrier coverage  823 samples, 0 unguarded
  fence jogs >10st  0

tools/probe_jog.luau

@@ -0,0 +1,107 @@
+-- Slip walls measured CLEAN (0 missing, 0 deviation, 0.00 lateral step), so
+-- neither marked defect is on the ramp decks themselves. Prime suspect is the
+-- suppression boundary I introduced: across 527..548 the parapet is forced back
+-- to the mainline edge, while 510..526 and 549..565 still carry it relocated
+-- OUT on the aux lane's outer edge (~26 studs further). At samples 527 and 549
+-- that is a ~26-stud lateral JOG -- a barrier that visibly sticks out and ends
+-- in a stub. And the gore between mainline barrier and ramp wall start may be
+-- open -- the missing-barrier oval.
+--
+-- Measure signed lateral offset of every Barrier from the mainline centreline,
+-- walk 505..570, and report steps + gaps.
+local out = {}
+local function say(s) table.insert(out, s) end
+
+local map = workspace:FindFirstChild("Map")
+if not map then return "Map MISSING" end
+local UP = Vector3.new(0, 1, 0)
+local function flat(v) return Vector3.new(v.X, 0, v.Z) end
+
+local deck, aux = {}, {}
+local bars = {}
+for _, d in ipairs(map:GetDescendants()) do
+	if d:IsA("BasePart") then
+		local k = d.Name:match("^Road_(%d+)$") or d.Name:match("^Deck_(%d+)$")
+		if k then deck[tonumber(k)] = d end
+		local a = d.Name:match("^AuxLane_(%d+)$")
+		if a then aux[tonumber(a)] = d end
+		if d.Name == "Barrier" then table.insert(bars, d) end
+	end
+end
+
+-- For each mainline sample, find the barrier nearest to that sample's plane on
+-- the LEFT side, and report its lateral offset from the centreline.
+say("sample | auxW | barrier lateral offset from centreline | step")
+local prevLat = nil
+local jogs, gaps = {}, {}
+for i = 505, 570 do
+	local d = deck[i]
+	if d then
+		local right = d.CFrame.LookVector:Cross(UP).Unit
+		local c = d.Position
+		-- gather barriers within half a sample spacing along the road axis
+		local best, bestLat = math.huge, nil
+		for _, b in ipairs(bars) do
+			if math.abs(b.Position.Y - c.Y) < 14 then
+				local rel = b.Position - c
+				local along = math.abs(rel:Dot(d.CFrame.LookVector))
+				local lat = rel:Dot(right)
+				if along < 22 and lat < 0 then -- LEFT side only
+					if along < best then best = along; bestLat = lat end
+				end
+			end
+		end
+		local auxW = aux[i] and aux[i].Size.X or 0
+		if bestLat then
+			local step = prevLat and math.abs(math.abs(bestLat) - math.abs(prevLat)) or 0
+			if step > 6 then
+				table.insert(jogs, ("%d(step %.1f)"):format(i, step))
+			end
+			if i % 4 == 0 or step > 6 then
+				say(("  %d | aux=%.0f | lat=%.1f | step=%.1f%s"):format(
+					i, auxW, bestLat, step, step > 6 and "   <<< JOG" or ""))
+			end
+			prevLat = bestLat
+		else
+			table.insert(gaps, i)
+			say(("  %d | aux=%.0f | NO BARRIER FOUND on left   <<< GAP"):format(i, auxW))
+			prevLat = nil
+		end
+	end
+end
+
+say(("JOGS (lateral step >6): %d %s"):format(#jogs, #jogs > 0 and table.concat(jogs, " ") or "(none)"))
+say(("GAPS (no left barrier): %d %s"):format(#gaps, #gaps > 0 and table.concat(gaps, ",") or "(none)"))
+
+-- Gore check: distance from each slip's FIRST wall to the nearest mainline
+-- barrier. A large value means an open mouth corner -- the missing-barrier oval.
+say("--- gore / mouth junction ---")
+for _, s in ipairs({ "PAWestSlip", "PAEastSlip" }) do
+	local first, firstK = nil, math.huge
+	local last, lastK = nil, -1
+	for _, d in ipairs(map:GetDescendants()) do
+		if d:IsA("BasePart") then
+			local wk = d.Name:match("^" .. s .. "_Wall_(%d+)$")
+			if wk then
+				local k = tonumber(wk)
+				if k < firstK then firstK = k; first = d end
+				if k > lastK then lastK = k; last = d end
+			end
+		end
+	end
+	if first then
+		local bd = math.huge
+		for _, b in ipairs(bars) do
+			if math.abs(b.Position.Y - first.Position.Y) < 16 then
+				local dd = (flat(b.Position) - flat(first.Position)).Magnitude
+				if dd < bd then bd = dd end
+			end
+		end
+		say(("%s: first wall seg %d at (%.0f,%.0f,%.0f) -> nearest mainline barrier %.1f"):format(
+			s, firstK, first.Position.X, first.Position.Y, first.Position.Z, bd))
+		say(("   last wall seg %d at (%.0f,%.0f,%.0f)"):format(
+			lastK, last.Position.X, last.Position.Y, last.Position.Z))
+	end
+end
+
+return table.concat(out, "\n")