[sim] round 4 NOTES

Research provable end-to-end on DATA's real tree (realtech.test.ts), not
just a fixture. Cooler aura ~triples a hot generator's run. Constants
exported. Reference factory ships slabs.

For the orchestrator:
- the demo needs one line from you: the reference build uses two gated ids
  so it is a post-research save now. Dispatched cold it comes up 100 draw
  vs 80 gen and browns out -- I watched it. referenceFactoryTech(data)
  names the techs; testkit.grantResearch() opens them. Proposing a dev-only
  {kind:'grantResearch'} command instead of importing test helpers
- DATA fixed the tech bootstrap mid-round and was right to: it was circular
  and 0 of 24 techs were affordable at start
- asic-cooler still has no coolRadius, so its aura is inert in the game
- cooling cap 0.05/tick is my call; reasoning in NOTES

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

fktry/lanes/LANE-SIM.md

@@ -388,3 +388,107 @@ NEXT (round 4 if asked)
 - The Correction / parity mites (M3's enemy).
 - Spatial heat + `coolRadius`, if the ASIC cooler is meant to mean something.
 - A self-upgrading bloom recipe, if you want the codex's literal loop.
+
+### Round 4 — 2026-07-17 — Opus 4.8
+
+SHIPPED
+- **Research v1 + the v4 gating rule.** `kind:'lab'`, `setResearch`, `snapshot.research`,
+  the `researched` event, and gating: any id a tech's `unlocks` names is refused by
+  `place`/`setRecipe`/`setRecipeAt` until that tech lands; anything no tech mentions is free
+  forever (so data with no tech gates nothing). Labs take only packs the active tech still
+  needs, several labs feed one total, and research rides through save/load — as a *rule*,
+  not just a list, so a restored save can still build what it unlocked.
+- **A real research run on DATA's own tree** (`realtech.test.ts`): ore → demuxer → quantizer
+  → {crime → bricks, ringing → halos} + slurry → artifact bottler → SPATIAL PACK →
+  archaeology lab → tech complete → a recipe that was silently refused is now accepted.
+  Cold start, nothing granted. That's the DoD's unlock path on real data, not a fixture.
+- **Spatial cooling** (`coolRadius`): chebyshev from the footprint, auras stack by sum,
+  total capped at `HEAT_COOL_MAX`. Proven by measuring the actual shed rate, and a cooler in
+  range roughly triples a hot generator's run before it scrams (2.5× the ticks).
+- **`src/sim/constants.ts`** — 12 constants exported; DATA can import truth instead of
+  hand-copying numbers that go stale silently.
+- **Reference factory v4**: anchor-slab overflow tap → the demo now ships slabs (18 over 20k),
+  melt still first at tick 1248, still shipping at 20k, still **zero brownout ticks**.
+  `referenceFactoryTech(data)` derives which techs the layout needs, from the commands.
+- Also wired: `bandwidth.capacity`, `EntityState.scrammed`, `commissionQueue` in the snapshot
+  literal (v5-ready).
+- Verified in the browser as well as Node — identical ticks (1248 / scram 435), gating live
+  (`mv-extractor` refused while locked), `capacity: 900`, 23 techs unlockable, no console
+  errors. 65 sim tests; 318 across the repo.
+- Perf: **64.7× realtime** at 3,500 entities / 6,820 belt items (0.515 ms/tick, best of 3 on
+  a fresh page). Round 3 measured 74.9×. Nothing I added is meaningfully per-tick — `drainLabs`
+  early-outs when nothing is being researched, and cooling only touches machines that can
+  heat — so I can't attribute the gap, and I'm not going to pretend I can. It's either
+  environment noise or something small I haven't found; the headless benchmark I proposed last
+  round would settle it.
+
+DECISIONS
+- **Cooling cap = 0.05/tick, and the number is arbitrary but the reasoning isn't.** At 0.05 a
+  machine sheds a full 1.0 of heat in 20 ticks, which is already effectively instant. Past
+  that, more coolers buy nothing but still cost bandwidth and floor space — a stack that does
+  nothing reads as broken rather than generous. Retune freely; it's one constant now.
+- A cooler's aura excludes itself (its own `coolPerTick` is already counted once), and the
+  cache is invalidated on place/remove/rotate but *not* setRecipe — auras are geometry.
+- **A lab's appetite is whatever the active tech costs**, so switching targets re-ranks every
+  lane feeding it, and `setResearch` drops the route cache. Labs take only what the tech still
+  needs — a lab is not a warehouse, and packs hoarded for a tech nobody picked would strand
+  where no other lab could reach them.
+- Switching research targets **abandons** delivered packs rather than banking them per-tech.
+  Packs are the cost of indecision. Say the word if you'd rather bank them.
+- Completing a tech clears `active` rather than guessing a next target.
+- A machine placed while some of its recipes are locked defaults to its **first unlocked**
+  recipe, not `recipes[0]`.
+- `testkit.ts` (new, tree-shaken, imported by nothing in the app) grants research via a
+  save/load round-trip — the public API, not a back door. It's how a test says "this is a
+  late-game save" honestly.
+
+BLOCKED/BROKEN
+- **The demo browns out, and it needs one line from you.** The reference factory uses two
+  gated ids (`software-decoder` ← stream-software-decoding, `assemble-gop-i-only` ←
+  disc-i-only-cadence), so it is a post-research save by definition now. Dispatched cold
+  through `__fktryBus` it comes up **100 draw against 80 gen — BROWNOUT** with no decoder,
+  which I watched happen on screen. `__fktryDemo` must open those techs first;
+  `referenceFactoryTech(data)` tells you exactly which, and `testkit.grantResearch(sim, ids)`
+  will do it. The alternative is a dev-only `{kind:'grantResearch'}` command — your call,
+  since shipping testkit into main.ts is a bit grubby. A test pins both halves of this.
+- **DATA fixed the tech tree underneath me mid-round, twice, and it was the right call both
+  times.** When I started: no `kind:'lab'` machine existed at all, and every science pack was
+  made on the artifact-bottler which was itself locked behind a tech costing 10 analog-packs
+  — a hard circular dependency, **0 of 24 techs affordable at start**, the tree literally
+  unenterable. It now has `archaeology-lab`, spatial-packs craftable with zero research, and
+  6 techs affordable cold. `realtech.test.ts` is the tripwire if that bootstrap ever closes
+  over again — it's worth keeping for exactly that reason.
+  - Casualty of the churn: my first pass hard-coded `mosh-reactor` as "a gated machine" and
+    broke when DATA un-gated it an hour later. Round 1's lesson, relearned. The real-tree
+    tests now *derive* a gated and an ungated machine from the data.
+- `asic-cooler` has `coolPerTick: 0.02` but still no `coolRadius`, so its aura is inert in the
+  real game — it cools only itself, and it has no heat to shed. The mechanic is live and
+  tested on a fixture; DATA just needs the number. (This was my round-3 note; the field now
+  exists for them.)
+- Vitest caches JSON imports: I spent a while chasing a "gating is broken" ghost that was a
+  stale `tech.json` in `node_modules/.vite` while DATA edited underneath. Worth knowing if
+  anyone else sees data that doesn't match disk.
+
+CONTRACT REQUEST
+- None. v4 had everything.
+
+PROPOSAL
+- **A dev-only `{kind:'grantResearch'; tech: string[]}` command** would let `__fktryDemo` set
+  up a late-game board without importing test helpers into the app, and would give UI a way to
+  build a "sandbox" mode later. It's the cleanest fix for the brownout above.
+- The mosh reactor now needs **two** melt lanes in the reference layout, and that's a smell
+  worth knowing about rather than a bug: a machine pushes one item per output type per tick,
+  so a 3-melt craft trickles out over several ticks, and while its own lane is busy melt is
+  free to take any *other* rank-1 lane. Nothing is lost — it still reaches an uplink — but it
+  can wander into a lane meant for something else. If that ever bites somewhere it matters,
+  the fix is a per-item lane affinity, not more belts.
+- `Sim.save/load` are hardened in v4 and `testkit` depends on the blob shape (`.research`).
+  If the save format ever versions past 3, testkit moves with it.
+
+NEXT (round 5 if asked)
+- HF dust piles + mosquito swarms — the RNG is still unrolled and save/load already carries
+  its state, so wildlife lands without touching persistence.
+- The Correction / parity mites.
+- A headless perf benchmark, so the numbers above stop being anecdotes.
+- Research *time* (a lab currently counts a pack the tick it lands) if you want the tech tree
+  to feel like an investment rather than a purchase.