Wrong Yellow Matrix V2.4 — grounded fixes

- Fixed negative coordinate floor division. Scoreboard division already floors; subtracting 127/15/46336 shifted negative cells and supertiles one unit too far.
- True horizontal 96-block proximity scan over the current and eight neighbouring macrocell centres.
- Candidate chunks are forceloaded before marker creation; no more phantom queued counters without entities.
- Split connected components remain atomic paint-bucket jobs.
- Runtime engine marker version decoupled (5) from deterministic plan version (4).
- Current builders restart idempotently after reload; legacy V4 markers are removed.
- Queue selection no longer kills a real marker carrying a stale transient tag.
- Debug status now counts entities instead of reporting booleans.
- Starting hub is restored after every bottom-layer operation in macrocell 0,0.
