Add the leaf, duck, hippo and beak lines

[mLampir]

Before: besides the slime there were four egg lines (ember, stone, fox, cloud). The meadow and stream guardians gave no egg, and no wild pets of other lines lived in the forest or at the stream.

After: four more lines hatch, each with an egg, a baby, a child and two adults:

• Leaf: Sproutlet becomes Twiggle, or Needlenub if petted often. The egg comes from wild friends in the mushroom forest.
• Duck: Paddlet becomes Captain Quill, or Drakwing after 2 scuffles a day, won or not. The egg comes from the stream guardian.
• Hippo: Soakling becomes Lillypot, or Steamo if bathed twice a day. The egg comes from wild friends at the stream.
• Beak: Crestling becomes Parcelbeak, or Rapierre if it practiced tricks twice a day. The egg comes from the meadow guardian, Crowcomb.

Each child's lure (leaves, curl, towel stripe, goggles) shows where it is heading from its second day on.

How: the pixel art lives in tools/build_blob_sprites.py, which also generates the sheets. The new lines are registered in:

• life.ts: rules and characters.
• scene.ts: sheets, hints, umbrellas, Needlenub's bud and special-move particles.
• wild.ts, food.ts, home.ts and the locales.

The care diary now also counts battles, baths and tricks. The new state.guardian_eggs tracks which guardians gave their egg:

• A pet that got past a guardian before it had an egg gets that egg at the end of a later trip there.
• Old saves are migrated so that only the cave counts as given.

The docs are updated: pets.md (folded shut), gameplay.md and the README. The pictures in docs/images/pets/ were regenerated.

Closes #6, closes #7, closes #9, closes #10.

🤖 Generated with Claude Code

https://claude.ai/code/session_018m5J9V7X4cXFquP3ZLE9Le