feat(oil): tar seeps, the scanner's oil echo, full-height pockets, bio-lubricant, the Codex + Screelit's fruit x-ray (#2377)

[marceld23]

Closes #2377
Closes #2370
Closes #2371
Closes #2372
Closes #2373
Closes #2374
Closes #2375
Closes #2379

Oil is the only source of lubricant, which gates the jump generator, the drill tier, the speeder, the fabricator and the
clone tank. Measured with the real generator, it was almost impossible to find:

• 7–21 pockets per living world, ≈ 600 blocks apart;
• their tops ≈ 75 blocks under the surface;
• a terrain scanner that reached 20 blocks.

What changes

Terrain generation 22 (WorldDescription.OilSeepGeneration). Every older chunk stays bit-identical; golden
jungle-gen22 equals jungle-gen18 at the sample columns.

• Oil pockets never exceed 4 blocks of oil — the half-height reads hash bits the chance already zeroed (fix at terrain generation 22) #2370 — full-height pockets.
  • The half-height read hash bits 8–15. The hotspot keeps a pocket only when (h & 0xFFFF) < 0x4000, so bits 14–15
    were always 0 and ry never left 3.0–3.99.
  • Generation 22 reads the free bits 56–63. Oil per pocket goes from ≈ 465 to ≈ 975, and columns reach up to 10 oil
    instead of 4.
  • The tar shell stays sealed.
• Oil seeps: a visible tar chimney from about a third of the oil pockets to the surface (terrain generation 22) #2371 — oil seeps.
  • 3 pockets in 8 get a tar chimney from the shell up to the ground, a tar patch, and an oil puddle on dry land.
  • The chimney is claimed in the pocket's branch of the column loop: before topsoil, tunnels and caves.
  • Flora, trees, giant flora, Fifi plants, geysers, set dressing and settlement buildings keep off the patch
    (OilSeepNear, FootprintTouchesOilSeep).

Terrain scanner oil echo (#2372).

• WorldGenerator.FindOilPocketsNear reads the pocket grid directly: a handful of hash evaluations, no chunk.
• The scanner reports the nearest pocket within 800 blocks that still holds oil. It checks the pocket's heart in the
  live world, so a pumped-out pocket falls silent.
• The player sees:
  • a ping on the compass and the map (server RaisePingAt);
  • a violet marker;
  • a second toast with distance and depth.
• OreScanResult gets new fields: OilEcho, OilFound, OilX/Y/Z, OilEchoRange. They are contractless, and an
  older peer reads them as false/0, so no protocol bump.

Bio-lubricant (#2373).

• New refinery recipe: 3 biofuel + 1 carbon → 1 lubricant. Crude oil stays the cheaper route (1 + 1 → 2).
• It works on every world, including saves from before generation 18, which hold no oil at all.

Codex (#2374).

• New article Oil and Lubricant (DE + EN).
• Prospecting & Ore gets depth figures that match planets.json (diamond 46+, not 40+).
• The Planets chapter shows an oil line for the types that hold oil.
• The planet scan line now says "40–120 blocks".

Gas giant (#2375). It counts as living but never holds oil. The survey and CarriesOilPockets now exclude gas
worlds.

Texts.

• New and changed keys in all 14 languages. The twelve community languages are hand-written using each locale's own
  terms (fuel, refinery, compass, ping).
• pl tar: „Tar“ → „Smoła“.
• The coverage manifest is unchanged (100 %).

Docs. WORLD_GENERATION §39 (plus a note in §33), USER_MANUAL, TODO.md.

Screelit's report (#2379).

• What it looked like: looking past a fruit hanging under a crown showed the sky through the crown.
• Cause: a crown cell drew faces only toward air or glass, and a fruit (flora_*) counted as its own kind, so the leaf
  face toward it was culled. But the fruit is a thin cross billboard and never fills its cell.
• Fix:
  • Crown cells now also face cross-billboard plants and slim props (TraitThinPlant,
    ChunkMesher.FoliageFaceOpensTo).
  • Crown cells still seal each other.
  • Two new EditMode tests.

Not in this PR: #2376 (gadgets have no server-side reach check).

Tests

• OilSeepsWorldTests (8):
  • the half-height on both sides of the gate;
  • generation 21 matches generation 18 pocket for pocket;
  • about 3 in 8 pockets seep;
  • an unbroken chimney with a puddle and nothing on it;
  • no seep below generation 22;
  • the echo query matches the pocket function;
  • the gas giant;
  • dead worlds and old generations.
• OilEchoTests (4):
  • the scan finds the nearest pocket, and a pocket pumped dry falls silent;
  • the real scan pings;
  • no echo on a dead world;
  • the bio-lubricant recipe.
• Golden jungle-gen22.
• Unity EditMode ChunkMesherTreeFoliageEditModeTests (+2):
  • the face rule per block;
  • a leaf over a fruit keeps its bottom face.
• Local runs:
  • full server suite, Release, non-Slow: 4348/4348;
  • Unity player build: Success.

🤖 Generated with Claude Code