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_final.luau

@@ -0,0 +1,106 @@
+-- Re-verify after un-pinning index 2, and settle the 4 "bare" samples:
+-- 525L/526L/549L/550L sit at the ramp MOUTHS (west join=525, east join=551).
+-- An open parapet at a mouth is correct -- that is the doorway cars drive
+-- through, and the ramp deck's own walls take over. So check whether ramp deck
+-- + ramp wall actually cover those samples. If yes: not a hole. If no: a hole.
+local SS = game:GetService("ServerScriptService")
+local out = {}
+local function say(s) table.insert(out, s) end
+
+local mod = SS:FindFirstChild("MapBuilder", true)
+if not mod then return "MapBuilder NOT FOUND" end
+local fresh = mod:Clone()
+fresh.Name = "MB_fresh_" .. tostring(math.random(1e6))
+fresh.Parent = SS
+local ok, MB = pcall(require, fresh)
+if not ok then fresh:Destroy() return "require FAILED: " .. tostring(MB) end
+local ok2, err = pcall(function() MB.build() end)
+fresh:Destroy()
+if not ok2 then return "build ERROR: " .. tostring(err) end
+say("build OK")
+
+local map = workspace:FindFirstChild("Map")
+local parts = 0
+for _, d in ipairs(map:GetDescendants()) do
+	if d:IsA("BasePart") then parts += 1 end
+end
+say(("parts=%d"):format(parts))
+
+local deck, bars, slipAll = {}, {}, {}
+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
+		if d.Name == "Barrier" or d.Name == "EdgeRail" then table.insert(bars, d) end
+		if d.Name:match("^PA[EW][ae]stSlip") then table.insert(slipAll, d) end
+	end
+end
+
+local UP = Vector3.new(0, 1, 0)
+local function flat(v) return Vector3.new(v.X, 0, v.Z) end
+local function nearest(list, p, ytol)
+	local best = math.huge
+	for _, b in ipairs(list) do
+		if math.abs(b.Position.Y - p.Y) < (ytol or 14) then
+			local dd = (flat(b.Position) - flat(p)).Magnitude
+			if dd < best then best = dd end
+		end
+	end
+	return best
+end
+
+say("--- edge audit 520..555 (L side) ---")
+local realHoles = {}
+for i = 520, 555 do
+	local d = deck[i]
+	if d then
+		local right = d.CFrame.LookVector:Cross(UP).Unit
+		local edge = d.Position - right * (d.Size.X / 2 + 2)
+		local bd = nearest(bars, edge)
+		local sd = nearest(slipAll, edge, 20)
+		local covered = bd < 12 or sd < 30
+		if not covered then table.insert(realHoles, i) end
+		if bd >= 12 then
+			say(("  %d: barrier=%.1f slipStruct=%.1f -> %s"):format(
+				i, bd, sd, covered and "OK (ramp mouth)" or "HOLE"))
+		end
+	end
+end
+say(("REAL holes: %d %s"):format(#realHoles,
+	#realHoles > 0 and table.concat(realHoles, ",") or "(none)"))
+
+say("--- smoothness ---")
+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+)$")
+			if k then table.insert(segs, { i = tonumber(k), p = d.Position, cf = d.CFrame }) end
+		end
+	end
+	table.sort(segs, function(a, b) return a.i < b.i end)
+	local total, worst, worstAt, over = 0, 0, -1, 0
+	for j = 2, #segs do
+		local a, b = segs[j - 1].cf.LookVector, segs[j].cf.LookVector
+		local dth = math.deg(math.acos(math.clamp(a:Dot(b), -1, 1)))
+		total += dth
+		if dth > worst then worst = dth; worstAt = segs[j].i end
+		if dth > 5 then over += 1 end
+	end
+	local topY, level = segs[1].p.Y, 0
+	for _, sg in ipairs(segs) do
+		if math.abs(sg.p.Y - topY) < 0.5 then level += 1 else break end
+	end
+	say(("%s: total=%.1fdeg worst=%.1f@%d over5=%d level=%d"):format(
+		s, total, worst, worstAt, over, level))
+	say(("   start=(%.0f,%.0f,%.0f) end=(%.0f,%.0f,%.0f)"):format(
+		segs[1].p.X, segs[1].p.Y, segs[1].p.Z, segs[#segs].p.X, segs[#segs].p.Y, segs[#segs].p.Z))
+end
+
+local aux = 0
+for _, d in ipairs(map:GetDescendants()) do
+	if d:IsA("BasePart") and d.Name:match("^AuxLane_%d+$") then aux += 1 end
+end
+say(("AuxLane total=%d (want 30)"):format(aux))
+
+return table.concat(out, "\n")