Smelter/Furnace icon export scenario (a0c1f5)

Card a0c1f5 — echte Maschinen-Grafik als Item- und Machine-Icon

Item icons and Machines/Icons glyphs show the generic 'flame-in-house' instead of the real machine. Kai-agreed approach: throw-away scenario that renders the actual body canvas rather than screenshots.

Changes

• Tests/Scenarios/ExportSmelterFurnaceIcons.lua — boots the game harness (initializeTheGame), requires MakeSmelterFurnaceCanvas directly (analyst flag 3: beats the lazy GetCanvas double-tap), renders Grid[1] (default quad, flag 1), upscales the body canvas into 512×512 (full-asset linear, flag 4 — machine identity preserved), encodes PNG, writes via io into love.filesystem.getSource() (source tree, flag 5 — not the save dir).
• Targets: Tiles/Items/{Smelter,Furnace}.png + Tiles/Machines/Icons/{Smelter,Furnace}.png (all 512×512, scaled at draw time).
• Log via ScenarioLogger.Log — EXPORT wrote <path> per file, EXPORT done at end.

Run note

Needs a graphics context (canvas makers call love.graphics.newImage at require-time) → run through the build batch, not bare lovec. One-shot: run the scenario, copy nothing, files land in the source tree; the scenario is marked throw-away/delete-after-use. Tiles/Research/Smelter.png is the same stale art family — noted as optional out-of-scope per analyst nit.

Verified: luajit per-file + lovec .syntaxchk 4057/0.