feat: add a box to park, switch, and collect Pokémon

[Seb1337]

What

The app raises one active companion at a time, and finishing or rerolling a Pokémon discarded the previous one. This adds a box to store individual Pokémon, switch which one is active, and keep the ones you finish raising. Each stored Pokémon keeps its exact growth state (stageIndex/usedAtStage), so parking and resuming is lossless. Buying an egg now parks the current companion in the box instead of releasing it. The active companion still grows on its own — the box is opt-in.

Changes

• Model: CompanionState.box: [MonState], a stable MonState.id, and MonState.isComplete (set at graduation). Additive and lenient-decoded, so old saves load unchanged — no save-schema bump.
• CompanionStore.setActiveFromBox(id:) swaps a boxed Pokémon with the active one (growth preserved); graduated trophies can't be activated. graduate() keeps the finished Pokémon in the box (isComplete) alongside the existing dex record; applyUsage no longer re-grows a completed mon.
• dexSpecies / ownsSpecies / ownsShinySpecies now count boxed individuals, so switching the active companion never drops species from the Pokédex.
• buyEgg parks the active companion in the box (previously released it into the dex via releasedDexEntry, now removed) and starts the new egg immediately; canBuyEgg is unchanged (needs an active companion and funds). Price and rarity-guarantee mechanics are untouched.
• SaveTransfer: box is classified as progress, and sanitized() clamps box entries at the import trust boundary just like the active companion.

UI

• Collection gains a segmented Pokédex | Box (grouped on the left) with Catch log set apart on the right (CollectionSection).
• BoxGridView: paged 4×6 grid; inline confirm to set active (no sheets, matching the popover rule); names resolved through the cached line provider; a 🏆 badge marks graduated trophies, which show a short reason instead of the switch button.
• New localized strings for the box (en/ko/ja/es/fr/pt/de).

Verification

• Full test suite: 916 tests, 0 failures.
• Added coverage: box round-trip preserves token status; swap semantics and guards; graduation → box; final form ≠ graduated; graduated can't be activated; box species stay in the Pokédex across a switch; egg purchase parks instead of releasing (fresh + premium); import clamping of box entries; backward-compatible decode.

Note

The one change to the established loop is the egg purchase (release → park). Happy to split that into its own PR or gate it behind a setting — the box stands on its own without it.

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Edit (2026-09-10): Updated onto the latest main and resolved the conflicts.

• Integrates cleanly with the new individual-profile feature: boxed/parked Pokémon carry their profile, graduation and box swaps preserve it, and sanitized() clamps box entries' profiles too (shared clampMon helper).
• buyEgg now uses the new price(of:) API while keeping the park-in-box behavior; the now-unused releasedDexEntry was removed.
• Full test suite green after the merge: 1030 tests, 0 failures.