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_weave.luau

@@ -0,0 +1,123 @@
+-- Is the fused aux run genuine continuous pavement (a weaving section), or
+-- overlapping/duplicated parts? Checks per-sample coverage, duplicate indices,
+-- and the width profile across both mouths.
+local ws = game:GetService("Workspace")
+local map = ws:FindFirstChild("Map")
+if not map then return "NOMAP" end
+
+local seen, dupes = {}, 0
+local byIdx = {}
+for _, d in ipairs(map:GetDescendants()) do
+	if d:IsA("BasePart") then
+		local i = tonumber(d.Name:match("^AuxLane_(%d+)$") or "")
+		if i then
+			if seen[i] then dupes += 1 end
+			seen[i] = true
+			byIdx[i] = d
+		end
+	end
+end
+
+local out = {}
+local function say(s) table.insert(out, s) end
+say(("duplicate AuxLane indices: %d -> %s"):format(dupes, dupes == 0 and "PASS" or "FAIL"))
+
+-- Walk 505..570 and report which samples have lane and how wide.
+local missing = {}
+local prof = {}
+for i = 505, 570 do
+	local p = byIdx[i]
+	if p then
+		table.insert(prof, ("%d:%.0f"):format(i, p.Size.X))
+	else
+		table.insert(missing, i)
+		table.insert(prof, ("%d:--"):format(i))
+	end
+end
+say("width profile (sample:width, -- = no lane):")
+say("  " .. table.concat(prof, " "))
+say("gaps in 505..570: " .. (#missing > 0 and table.concat(missing, ",") or "none"))
+
+-- The only gaps should be the ramp noses (the ramp deck covers those).
+-- Derive coverage from the ACTUAL ramp deck parts, but test the point where
+-- the AUX LANE would sit (deck edge + half lane width) -- NOT the mainline
+-- centreline. Testing proximity to the centreline marked 26 samples as "nose"
+-- because the ramp spirals past them at other heights, which would mask any
+-- real hole and make this check vacuously pass. The nose test must also match
+-- in HEIGHT: a ramp 50 studs below the deck does not cover the deck's edge.
+local samples = require(game:GetService("ReplicatedStorage")
+	:WaitForChild("Shared"):WaitForChild("Circuit")).samples
+local decks = {}
+for _, d in ipairs(map:GetDescendants()) do
+	if d:IsA("BasePart") and d.Name:match("Slip_Deck_") then
+		table.insert(decks, d)
+	end
+end
+
+local HALF, AUXW, SIDE = 30, 26, -1
+local function auxPointAt(i)
+	local n = #samples
+	local a = samples[((i - 1) % n) + 1]
+	local b = samples[(i % n) + 1]
+	local f = b.pos - a.pos
+	f = Vector3.new(f.X, 0, f.Z).Unit
+	local r = Vector3.new(-f.Z, 0, f.X)
+	return a.pos + r * (SIDE * (HALF + AUXW / 2)), a.pos.Y
+end
+
+local NOSE, noseWhy = {}, {}
+for _, i in ipairs(missing) do
+	local p, deckY = auxPointAt(i)
+	for _, d in ipairs(decks) do
+		local flat = (Vector3.new(d.Position.X, 0, d.Position.Z)
+			- Vector3.new(p.X, 0, p.Z)).Magnitude
+		local dy = math.abs(d.Position.Y - deckY)
+		-- Must overlap the lane footprint horizontally AND be at deck level.
+		if flat <= AUXW and dy <= 6 then
+			NOSE[i] = true
+			noseWhy[i] = ("%s flat=%.0f dy=%.0f"):format(d.Name, flat, dy)
+			break
+		end
+	end
+end
+local noseList = {}
+for i in pairs(NOSE) do table.insert(noseList, i) end
+table.sort(noseList)
+say(("ramp-nose-covered gaps (%d): %s"):format(#noseList, table.concat(noseList, ",")))
+for _, i in ipairs(noseList) do
+	say(("    %d covered by %s"):format(i, noseWhy[i]))
+end
+
+local lo, hi = math.huge, -1
+for k in pairs(byIdx) do
+	lo = math.min(lo, k); hi = math.max(hi, k)
+end
+local bad = {}
+for _, i in ipairs(missing) do
+	-- Samples outside the lane's own extent are not holes; only flag gaps that
+	-- sit strictly between the first and last aux segment.
+	if i > lo and i < hi and not NOSE[i] then table.insert(bad, i) end
+end
+say(("lane run extent: %d..%d"):format(lo, hi))
+say(("non-nose gaps inside the lane run: %s -> %s"):format(#bad > 0 and table.concat(bad, ",") or "none",
+	#bad == 0 and "PASS (only ramp noses uncovered)" or "FAIL (hole in pavement)"))
+
+-- Between the two mouths, is the lane continuously full width (a real weaving
+-- section) rather than tapering out and back in?
+local weaveMin = math.huge
+local weaveTested = 0
+for i = 528, 548 do
+	local p = byIdx[i]
+	if p then
+		weaveTested += 1
+		weaveMin = math.min(weaveMin, p.Size.X)
+	end
+end
+if weaveTested == 0 then
+	say("weave section: FAIL nothing tested")
+else
+	say(("weave section 528..548: %d segs, min width %.1f -> %s")
+		:format(weaveTested, weaveMin,
+			weaveMin >= 24 and "PASS (continuous full-width weaving lane)" or "TAPERS"))
+end
+return table.concat(out, "\n")