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_kinks.luau

@@ -0,0 +1,73 @@
+-- PAEastSlip turns 216deg vs PAWestSlip's 56.5deg -- nearly 4x. That is the
+-- "looks terrible" the user means. Find WHERE the turn concentrates: is it a
+-- smooth long curve, or a few violent kinks? Per-segment heading deltas tell us.
+local out = {}
+local function say(s) table.insert(out, s) end
+
+local map = workspace:FindFirstChild("Map")
+if not map then return "Map MISSING" end
+
+for _, s in ipairs({ "PAWestSlip", "PAEastSlip" }) do
+	local segs = {}
+	for _, d in ipairs(map:GetDescendants()) do
+		if d:IsA("BasePart") then
+			local k = d.Name:match("^" .. s .. "_Deck_(%d+)$")
+			if k then table.insert(segs, { i = tonumber(k), p = d.Position, cf = d.CFrame, sz = d.Size }) end
+		end
+	end
+	table.sort(segs, function(a, b) return a.i < b.i end)
+	if #segs == 0 then say(s .. ": absent") continue end
+
+	local deltas = {}
+	for j = 2, #segs do
+		local a = segs[j - 1].cf.LookVector
+		local b = segs[j].cf.LookVector
+		local dth = math.deg(math.acos(math.clamp(a:Dot(b), -1, 1)))
+		table.insert(deltas, { i = segs[j].i, d = dth, p = segs[j].p })
+	end
+
+	-- worst kinks
+	local sorted = {}
+	for _, v in ipairs(deltas) do table.insert(sorted, v) end
+	table.sort(sorted, function(x, y) return x.d > y.d end)
+
+	local sum = 0
+	for _, v in ipairs(deltas) do sum += v.d end
+
+	say(("%s: total=%.1fdeg  mean=%.2fdeg/seg  n=%d"):format(s, sum, sum / #deltas, #deltas))
+	local worst = {}
+	for j = 1, math.min(8, #sorted) do
+		table.insert(worst, ("seg%d=%.1f"):format(sorted[j].i, sorted[j].d))
+	end
+	say("   worst kinks: " .. table.concat(worst, " "))
+
+	-- how many segments exceed a smooth-curve threshold?
+	local over = 0
+	for _, v in ipairs(deltas) do if v.d > 5 then over += 1 end end
+	say(("   segments turning >5deg: %d"):format(over))
+
+	-- segment length consistency (uneven lengths also read as ugly)
+	local lmin, lmax, lsum = math.huge, -math.huge, 0
+	for j = 2, #segs do
+		local L = (segs[j].p - segs[j - 1].p).Magnitude
+		lmin = math.min(lmin, L); lmax = math.max(lmax, L); lsum += L
+	end
+	say(("   seg spacing: min=%.1f max=%.1f mean=%.1f  totalRun=%.0f"):format(
+		lmin, lmax, lsum / (#segs - 1), lsum))
+
+	-- vertical profile: where does it drop?
+	local topY = segs[1].p.Y
+	local level = 0
+	for _, sg in ipairs(segs) do
+		if math.abs(sg.p.Y - topY) < 0.5 then level += 1 else break end
+	end
+	local steep = 0
+	for j = 2, #segs do
+		local dy = math.abs(segs[j].p.Y - segs[j - 1].p.Y)
+		local dxz = (Vector3.new(segs[j].p.X, 0, segs[j].p.Z) - Vector3.new(segs[j - 1].p.X, 0, segs[j - 1].p.Z)).Magnitude
+		if dxz > 0.1 and (dy / dxz) > 0.12 then steep += 1 end
+	end
+	say(("   level-run=%d  segments steeper than 12%%: %d"):format(level, steep))
+end
+
+return table.concat(out, "\n")