continue. FIX ROUND 4, with the design already decided so you only have to IMPLEMENT it. Your last attempt at this ran 45 minutes and made no edit: two single thoughts of about 32,000 tokens each (11 minutes apiece) and three 4-minute chat compactions. Do not re-derive the design. If something is ambiguous, pick the simplest option, write one line about it in NOTES.md and move on. Keep your reasoning short. Work in small steps: one edit, run the measuring tool, look at two crops, next edit.

CONTEXT: three independent reviewers checked your round-3 final.mp4. Everything from round 3 is confirmed except ONE item: the callout leader lines. In index.html (lines ~159-193) each leader group has fixed polyline segments from the pill at (1360,765) to a bend and a last segment whose end follows an anchor; the dots are circles #leaderDotA..D2 filled #8E99A6, the same grey as the steel, so you cannot see them, and the anchors are fixed spec points ABOVE the valve heads (at (856,364) and (944,364)) so they land on the stem. The bend at (1000,310) for B/C/D also sits in the exhaust port and scratches across the red particle trail.

THE DESIGN (implement exactly this):
1. Colour: every leader line and dot is NOT steel grey. Lines: white #F2F5F8, stroke-width 2, drawn over a dark under-stroke #0E1116 stroke-width 5 (a halo, so it reads on steel and on dark). Dots: fill #F2F5F8, stroke #0E1116 stroke-width 2, r 6. Do not use any gas colour (blue #3FA7FF, yellow #FFD23F, orange #FF7A1A, red #E5383B), they mean something in the legend.
2. Route (all callouts): pill corner (1360,765) -> straight line up to a point on a horizontal 'bus' above the engine -> along the bus -> straight DOWN the labelled part's own axis to the dot. The final vertical segment must be exactly vertical every frame: set its x1 AND x2 to the zoomed anchor x (tx), so the camera zoom never skews it. Bus heights (screen y, before zoom; they are drawn in screen space and may stay unzoomed): A/A2 (intake) y=125; C/C2 (exhaust) y=140; B/B2 (plug) y=110; D1/D2 (between valves) y=95. Bus start x for the diagonal from the pill: A 1032, C 1040, B 1048, D 1056 (pick other values if lines would cross each other, but never route through the engine window x 580-1240, y 70-1010 except for the vertical drop).
3. Anchors (the DOT position, per frame): A/A2 = centre of #valveHeadIntake (x = its centre x, y = its centre y, so it follows the head as it opens downward); C/C2 = centre of #valveHeadExhaust (same); B/B2 = the plug tip: x=900 (zoomed), y = roof y minus 8 px, i.e. the lowest visible part of the plug; D1/D2 = on the bore axis at the roof, y = roof y minus 4 px. Compute them with the same zoom transform you already use (zsx/zsy) from the same numbers that place the valve head, so they cannot drift.
4. Z-order: the whole leaderLinesTop group (lines and dots) goes AFTER every engine part, the cams, springs, plug and the head casting in the SVG so nothing covers a dot. Keep the fade of each group with its callout.
5. Delete the old fixed anchor table values that no longer apply; keep the second-cycle duplicates (A2..D2) in sync.

CHECK (the measuring tool has three leader checks; they all FAIL today):
  node measure_engine.mjs --times 5.5,7.33,8,11.5,16,21.5,24,27.5,31 --shots workspace/meas4
They must all pass together with every other check. Then look at head crops at 5.5, 11.5, 16, 24 (vision_analyze, one call at a time: it is for text and colour only): the white line must run down its own valve or plug and end in a clearly visible dot on that part.

OTHER SMALL ITEMS:
 a. Dial needle: the shaft runs through the letters of 'IN' (near t=1.9) and 'EX' (near t=11 and t=26). Draw the IN and EX labels above the needle in z-order.
 b. HUD rounding: the HUD truncates (329.85 shows 329). Look at SPEC.md for the rule; if it says round, round; if it says floor or nothing, leave it and say which in REPORT.md.

THEN: back up final.mp4 to final_v3.mp4 and review.mp4 to review_v3.mp4 BEFORE rendering; render review.mp4 and final.mp4; ffprobe gate (h264, 1 video stream, 1920x1080, 30/1, 32.0 s +/-0.05, no audio); append round 4 to REVIEW.md, REPORT.md, NOTES.md. player.html is an iframe of index.html, so it needs no rebuild; re-run the 3-time player screenshot comparison once. Final report: per item fixed or not fixed with the measuring-tool output, the gate, files written; be honest about anything still imperfect.

NOTE ON YOUR SETUP (changed at 12:15): your context window is now 491,520 tokens (compaction at about 295K by your count instead of 92K), so you will be compacted far less often, and Maya now runs 2 seats instead of 4: you are the only user, so nothing queues. Long prompts are fine; reading a 100K prompt cold takes about 23 s. Do not spend time on any of that: it only explains why your calls will be quicker and your chat longer.