production lines: resolve conveyor -> island placement mapping

The recipe conveyors (game_conveyor_<product>_epb) are placed as named child GameObjects
in the island_* prefabs (islands_assets_all.bundle), NOT via energy_grid (power grid only)
or any config asset. New extractor bundle/extract_conveyor_placements.py walks every island
prefab and cross-references production_lines.json -> extracted/conveyor_placements.json.

Result: Factorio (energyRods, 80mmT3Cannon, contactGrenades, armorPiercingRocket),
Kaiserplatz (energyRods, 40mmT3Cannon), Demo_Wunderinsel (70mmT3Cannon), DeusExMashineSmall
(computingModules, coralDust), testIsland(+Tramplers) (the 4 base test conveyors).

Corrects the earlier "Armory = Sprengstofffabrik hosts explosives" guess: the
LittleFactory/LittleFactoryArmory islands place NO recipe conveyors; grenades/rockets are
on Factorio. Unplaced blueprints: explosiveSmall, mechanicalParts (+ the plural
armorPiercingRockets, whose singular-named instance is on Factorio).

docs/PRODUCTION_LINES.md

@@ -54,18 +54,41 @@ Key item ids seen here: `item_crystalHandles` = *Raw Aurogen Crystal*,
 `extracted/items_registry.json` / `extracted/item_names.json` (built from
 `CheatItemDefinitionsData`).
 
-## Island placement — open lead
+## Island placement — RESOLVED
 
-Which factory/island runs which conveyor is grouped by the
-`energy_grid_*_epb.prefab` blueprints in the same bundle:
-`Wunderinsel`, `Kaiserplatz`, `DeusExMachine`, `Factorio`, `LittleFactory1-3`,
-`LittleFactoryArmory1-3`, `TestFactory`. The **`…Armory`** groups are the likely
-**Sprengstofffabrik** (explosives factory) host for the explosive / grenade / rocket /
-cannon conveyors.
+Each recipe conveyor is placed as a **named child GameObject** (`game_conveyor_<product>_epb`)
+in the `island_*` prefab's Transform hierarchy inside `islands_assets_all.bundle`. It is NOT
+in the `energy_grid_*` blueprint (that holds only `EnergyGridDataComponent` — the power grid)
+and NOT in any config / designed-environment asset. Extract with:
 
-**Not yet resolved:** an `energy_grid_*` blueprint's Odin data references its conveyors by
-**entity reference, not item-id string** (a string scan of its serialized bytes finds no
-`game_conveyor_*` / `item_*` ids). So mapping recipe → specific island needs the **island
-prefab placements** in `islands_assets_all.bundle` (the `island_*` / fort / `loc_event_*`
-prefabs, where `Sprengstofffabrik` is an i2 `Toponyms/` name), not the conveyor or
-energy_grid EPBs alone. That linkage is the next step if island attribution is wanted.
+```bash
+venv/bin/python bundle/extract_conveyor_placements.py   # -> extracted/conveyor_placements.json
+```
+
+This walks every island prefab, collects the `game_conveyor_<product>` children (with local
+position) and cross-references each against `production_lines.json`. Result for this build:
+
+| Island | Recipe conveyors placed |
+|---|---|
+| `island_Factorio` | energyRods, 80mmT3Cannon, contactGrenades, armorPiercingRocket* |
+| `island_Kaiserplatz` | energyRods, 40mmT3Cannon |
+| `island_Demo_Wunderinsel` | 70mmT3Cannon |
+| `island_DeusExMashineSmall` | computingModules, coralDust |
+| `island_testIsland`, `island_testIslandTramplers` | the 4 `base*` conveyors (inv↔large test combos, incl. the `1x wineBox → 1000x coinCrown` one) |
+
+Notes / corrections:
+- The earlier guess that the **`…Armory` (Sprengstofffabrik)** islands host the explosive /
+  grenade / rocket conveyors is **not supported by the placements**: `island_LittleFactory01-03`
+  and `island_LittleFactoryArmory01-03` exist (each has an `energy_grid_*`) but place **no**
+  recipe conveyors at all. The grenade (`contactGrenades`) and rocket (`armorPiercingRocket`)
+  lines are on **Factorio**. Factorio is the main multi-product factory here.
+- `*` Factorio's child is named `game_conveyor_armorPiercingRocket` (singular) while the recipe
+  blueprint is `game_conveyor_armorPiercingRockets` (plural) — a name mismatch; same line
+  (→ `3x item_rocketLauncherAmmoArmorPiercing`).
+- Defined-but-**unplaced** recipe blueprints in this build: `armorPiercingRockets` (plural;
+  the singular instance is on Factorio), `explosiveSmall` (→ `5x item_c4Dynamite`),
+  `mechanicalParts` (→ `item_resourceMetal_t1`).
+- Infrastructure conveyors (`game_conveyorSlotInput`, `…OutInventory`, `…OutLargeItem`,
+  `…InSwitch`) accompany the recipe ones on each factory island — these are the input/output
+  ports, not recipes (no underscore after `conveyor` = generic infra; `game_conveyor_<x>` =
+  recipe line).