Phase 5: breeding with Cobbreeding, Ditto a rare Deep Dark find

Adrian (2026-10-31): add Cobbreeding without a gate; only Ditto should
be rare, in an endgame area or gated behind something else.

- Cobbreeding 2.4.1 (Modrinth only) and Cloth Config (client) in the
  pack; Cobblebase's hatchery takes Cobbreeding's eggs.
- Ditto moved from Button Isle to the Deep Dark with both of Cobblemon's
  entries (rare in slime chunks, ultra-rare elsewhere): zone_spawns.py
  pins take {"zone", "all_entries"}; Deep Dark target +1, Button Isle -1
  so no other line moved; Southwold and Frostpeak guardians pinned (they
  tie on base stats and flipped between runs).
- HMs' Trainer Ditto is made uncatchable; it still trades.
- check_deps.py skips other-side dependencies; Cobbreeding's harmless
  client-mixin log line allowlisted.
- Self-tests cobbreeding_eggs_fit_the_hatchery, trainer_ditto_cant_be_caught;
  docs, balance table, Phase 5 checklist.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

docs/checklists/phase-5.md

@@ -19,6 +19,7 @@
   - Mining drops its loot at the Pokémon's feet; an **Item Gatherer** in the same pasture carries it into the chest (Cobblebase's design). Without one, the loot despawns after 5 minutes.
   - A gated job doesn't stick: assigned to a Pokémon that doesn't pass, it's taken back at once (gone from Buffs → Active) with a message saying what the Pokémon needs. Automated: `gated_jobs_are_taken_back`.
   - Mining, the Ore Finder and the Evolution-item Finder only give the ores and evolution stones of the pasture's zone; Mining no longer gives type gems. Automated: `base_jobs_dig_their_zones_ores`.
+- **Breeding (2026-10-31):** Cobbreeding is in, without a gate; Cobblebase's hatchery takes its eggs. Ditto only spawns in the Deep Dark now, and rarely; HMs' Trainer Ditto can't be caught. Automated: `cobbreeding_eggs_fit_the_hatchery`, `trainer_ditto_cant_be_caught`.
 - **Shoulder passives:** a shoulder Pokémon gives an effect by type (Flying slow falling, Electric speed, Rock/Ground/Steel haste; gated: Fire warmth, Ice frigidness, Water water breathing, Ghost/Dark night vision). Automated: `shoulder_pokemon_give_passives`.
 
 ## In game (Prism instance)
@@ -31,6 +32,9 @@
 - [ ] With a pasture on Button Isle, Mining brings coal, tumblestones, cobblestone, gravel, flint and fossils, but no iron, copper, gold, diamonds or gems. In Westmarch it brings raw iron and thunder stones instead of coal.
 - [ ] Craft and place a Power Block in survival: no guardian needed.
 - [ ] Put Pidgey (or another Flying type) on your shoulder: slow falling. A low-level Fire type on your shoulder: a message about warmth; with a sun stone or lapis held, Cold Sweat's warmth shows.
+- [ ] Put two compatible Pokémon (e.g. two Eevee, or any Pokémon and a Ditto) in a Pasture Block and switch breeding on with its button: after 7–12 minutes an egg sits in the pasture's nest. Carry it: it hatches after a while.
+- [ ] Put an egg in a chest next to a pasture with a Pokémon working as Egg Hatcher (Deep Dark gate: Lv 60, or holding a diamond or dusk stone): it takes the egg and hatches it.
+- [ ] Throw a ball at HMs' Trainer Ditto: it can't be caught, but it still trades.
 - [ ] Look at the other abilities your Pokémon offer on the wheel (Cut, Strength, Surf boosts, ...) and note any you want switched off or tuned.
 
 ## Ask Adrian