[render] round 4 NOTES

Verification numbers; the lock-rule divergence with UI (they were right, I was
wrong — the scrammed lesson misapplied); the showroom overflow postmortem; one
contract request (an inspected-entity channel for placed-and-selected auras).

Notes that round 3's MODELBEAST manifest is stale — ?showroom is the live one.

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

fktry/lanes/LANE-RENDER.md

@@ -422,3 +422,97 @@ Cheapest real fixes, in order:
 - Real MODELBEAST assets through `?showroom`; splitter lamp driven by real round-robin
   state instead of a timer; bloom-loop belt tell; HF dust piles; wildlife; save/load
   camera state; LOD/culling if a megabase ever drags the frame.
+
+### Round 4 — 2026-07-17 — Opus 4.8
+
+**SHIPPED** — all 4 orders + housekeeping, verified against LANE-DATA's real v4 data
+(which landed mid-round: 29 machines, 60 items, `archaeology-lab`, `asic-cooler
+coolRadius:2`, `accent` on 8 machines) and UI's real migrated flow.
+
+1. **Ghost keys off `mode`.** The `'__remove'` sentinel is ignored — mode is the truth,
+   and the `REMOVE_DEF` constant is deleted from this lane. Verified through UI's own
+   REMOVE tab: `selection()` → `{mode:'remove'}`, demolition decal + wash on the mosh
+   reactor's whole 3×3.
+2. **Locked-machine ghost.** Padlock-amber `#ffb02e` — deliberately not the occupied-red,
+   because "not yet" and "not here" are different sentences. A padlock floats above,
+   tinted by the era gating it. Verified: `telecine-puller` → amber ghost + `#d8a24a`
+   reel brass; `asic-cooler` → amber + `#5fd08a` broadcast phosphor.
+   - **Era tell needed its own palette.** `ERA_SKIN.tint` can't do this job: it's a
+     multiplier tuned to leave DATA's chassis alone (stream is literally `#ffffff`), so
+     three of five eras would have told you nothing. Added `ERA_TELL` — five hues chosen
+     to be told apart, used as signal rather than surface.
+3. **Cooler auras.** Verified on `asic-cooler` (fp 2×2, coolRadius 2) → **6×6 tiles**,
+   centred on the ghost, dashed + tick-marked, no fill.
+   - **It's a rectangle, not a ring.** `coolRadius` is CHEBYSHEV from the footprint, so
+     the cooled region is the footprint grown by r on each side. A circle would have been
+     prettier and would have lied — the corners it left out are cooled, and players would
+     plan around a boundary that doesn't exist. Drawn in the geometry the sim measures in.
+4. **Lab visuals.** `archaeology-lab` (kind `lab`, 3×3) renders as a bench + the "bottled
+   artifact triptych" (§2) — three out-of-phase pulsing bottles. Verified geometry
+   `Box,Cylinder,Cylinder,Cylinder` and **`accent` consumed from data**: bottles emissive
+   `#ffc24a`, exactly DATA's authored value.
+5. **Housekeeping.** Splitter lamp left timer-driven as approved. Showroom absorbed the
+   new catalog — see the bug below.
+
+**VERIFIED**
+- Perf standing rule holds: 500 entities + 2,000 items at **3.6ms/frame**, 5 instanced
+  draw calls. (R1 3.2 / R2 3.6 / R3 3.3 / R4 3.6 — auras, padlocks and the locked path
+  cost nothing measurable.)
+- Showroom absorbs 29 machines + 60 items, all five eras present, hall inside the world.
+
+**DECISIONS**
+- **Matched LANE-UI's lock rule rather than my own, and it was a real divergence.** My
+  first cut treated absent `research` as "nothing is locked" — don't lie when the field
+  isn't wired. UI's `research.ts` reads the same rule the opposite way: nothing has
+  completed, so everything gated shows its padlock. **UI is right and I was wrong**: this
+  is the `scrammed` lesson misapplied. There, the field's absence meant the sim hadn't
+  wired a *behaviour*; here the rule is satisfiable from data alone and the contract says
+  "until that tech completes". Left unresolved, the build bar would have padlocked a
+  machine while the ghost waved it through — on the same screen. Also matched their
+  first-tech-wins tie-break for ids unlocked by two techs: a data bug either way, but we
+  must both blame the same tech.
+- **Buffer fill now reads `bandwidth.capacity`** instead of re-summing `bufferCap`
+  locally. v4 publishes the total; a second copy of the sim's arithmetic in this lane is
+  exactly what the scram latch taught us not to keep. Falls back to the local sum only
+  while the field is absent.
+- **`MachineDef.accent` wins outright, no legibility floor** — same reasoning as
+  `def.color`: explicit art-direction is a decision; the floor exists for *derived*
+  colours, which are incidental.
+
+**BLOCKED/BROKEN** — nothing blocking.
+- **The showroom bug I predicted last round arrived, and my fix was half a fix.** Round 3
+  noted the item hall would overflow when the catalog grew. It did (51 → 60 items), but
+  the failure wasn't the one I expected: the *machine* hall grew to 5 rows, ate the depth
+  budget, collapsed the item grid to **one row of 60 columns — a 206-tile row across a
+  64-tile world**. My round-3 "adaptive" fit budgeted depth only. Now fitted to both axes,
+  and it `console.warn`s if the catalog ever exceeds the hall rather than silently
+  stacking items off-world. Lesson: an auto-fit that constrains one axis just moves the
+  overflow to the other one.
+- **"Placed-and-selected" auras aren't reachable** (order 3's third case). `SelectionState`
+  is `build | remove | null` — UI's click-to-inspect selection has no contract channel, so
+  a placed cooler rings on **hover**, not on inspect. Hover covers the same intent for
+  now; see CONTRACT REQUEST 1.
+- Two tests fail repo-wide (`sim/reference.test.ts`, `ui/live.test.ts`) — both SIM/UI
+  in-flight research work, neither imports `src/render`. tsc is clean repo-wide.
+
+**CONTRACT REQUEST**
+1. **An inspected-entity channel**, if you want order 3's "placed-and-selected" case for
+   real. Cheapest shape: extend `SelectionState` with `{ mode: 'inspect'; entity: number }`,
+   or add `UIBus.inspected?(): number | null`. Renderer has no other way to know what the
+   player clicked. Low priority — hover already answers "what does this cool?".
+2. Nothing else. v4 granted round 3's `setGhostMode` ask (as `setGhost(..., mode)`) and it
+   landed clean; the sentinel bridge can die in v5 whenever you like — this lane no longer
+   reads it.
+
+**NOTE FOR THE MODELBEAST ORDER** — the manifest in round 3's NOTES is now stale: DATA
+added 6 machines (`roto-bench`, `matte-bath`, `optical-printer`, `chroma-keyer`,
+`neural-keyer`, `archaeology-lab`) and the tech tree now gates 13 across all five eras.
+`?showroom` is the live manifest — it labels every machine with its exact `<asset>.glb`
+filename and era, and re-reads data on load, so it can't go stale the way a table in a
+doc does. Read it there rather than from round 3.
+
+**NEXT (round 5 candidates, not self-assigned)**
+- Real MODELBEAST assets through `?showroom`; heat-shimmer suppression reading as
+  *relief* inside a cooler's rectangle once SIM lands spatial cooling; bloom-loop belt
+  tell; HF dust piles; wildlife; save/load camera state; LOD/culling if a megabase ever
+  drags the frame.