OPEN FORKS (V3, user directive): the line forks now and answers later

'Forking currently exists as a singular generative pass only. It should
allow for unresolved forks to resolve in later generation up to a
point.' — the braid clause may now leave its fork OPEN at the segment
boundary; the successor segment MUST open with the continuation and
merge within OPEN_BRAID_CAP total cells (bounded irresolution).

- path.ts: HeadState.openBraid carries {side, offset, cells, laneMods,
  wanderer} across the boundary; tryBraidSide draws an open coin (new
  child stream — zero draw perturbation; the pinned braids simply drew
  closed) and runs the braid flush to the boundary (its straight tail IS
  the seam margin; profile keeps no return budget); planSegment resolves
  an inherited fork FIRST via tryBraidContinuation (longest-fits-first,
  profile walks the carried offset home, V1 merge at a pinned straight).
  The alt lane's own boundary corridor is checked with the
  hasFlatContinuation CONTRACT pose (the next cell past the seam — the
  bug that silently killed every open attempt in the first cut), and the
  successor-probe gate is what makes leaving a fork open safe: it only
  commits when the continuation actually plans.
- world.ts: fork mutation only on non-cont braids, merge only on
  non-open; alt chains build headless/tailless per case and hang
  contBraid/openBraid flags; EndlessSegment.braidContOf names the fork
  segment; lane-tag lip margins apply only at ends that ARE junctions.
- proxies.ts: a continuation chain's carrier window keeps its plain
  channel RIBBON (no fork mouth cut into an ordinary wall) and no fork
  composite; the merge composite emits as ever.
- Client: railFor + braidLaneFor + the rider hook carry the FORK
  segment's per-racer lane draw across the boundary (one draw per BRAID
  — no re-draw, no teleport-flip mid-braid); rival mirroring keys on the
  same label.
- Tests: V3 contract (open resolves next segment exactly once,
  braidContOf, side/laneMods carry, cap law, alt-lane PORT CONTINUITY
  across the seam <1e-6); closed contract scoped to closed braids; lip
  law knows boundary ends; drive() soak on grav-scan-32 crosses the
  boundary on BOTH lanes and merges home. Corpus: 136 braids / 14 open /
  0 planner failures over 160 seeds x 8 segments.
  205 green, check clean, endless goldens re-pinned.

commit

1abfbcfa2ee94e3884c5b119d2560237cdb8e1a3

parent

b82e133b3c8b151f300cbb23c2ff29c4de94422d

author

Dami <dami.etoile@gmail.com>