get_entities cannot see neutral-force entities — ground items block placement invisibly

[bdambrosio]

Found while running FLE's Lua stack in an unusual regime: a persistent multiplayer server where an LLM agent cohabits the map with a human player in real time (no fast-mode, real walking). Setup: https://github.com/bdambrosio/Cognitive_workbench (factorio/). We carry build-time patches for each of the issues we're filing; happy to turn any into a PR.

fle/env/tools/agent/get_entities/server.lua (lines 27/29): both
branches filter force = player.force. Loose items on the ground
(item-entity, force neutral) are invisible to observations, yet they
BLOCK building placement — so the agent repeatedly fails placements on
debris it cannot perceive (observed live: a mined drill's ore spill made
a tile unbuildable; the agent looped clearing "invisible" blockage by
trial and error). Resource patches have the same visibility gap.

Suggestion: include item-entity (and optionally resource) in results,
or add a forces parameter. We surface them host-side as per-type
aggregates with a bounding span, which reads well for the agent.

[bdambrosio]

Related bug found in pickup_entity while working the same ground-item terrain: it does support picking up ground items by item name (pickup_ground_item matches item.stack.name == entity), but the placed-entity search runs first as find_entities_filtered{name = entity}, which raises "Unknown entity name" for any name that is an item but not an entity prototype (e.g. iron-plate) — so the ground-item branch is unreachable for exactly the names it exists to serve. Guarding the entity search behind prototypes.entity[entity] (and rejecting names that are neither entity nor item prototypes with a clear error) fixes it.

Bonus defect in the same function: pickup_ground_item has a stray return true at the end of the first loop iteration, so a wrong-named first item within the search radius reports success while picking up nothing.

Both fixed in our build (factorio/build_mod.py FILE_FIXES in the repo linked above); happy to PR.