feat: integrate seatplus/esi-schema — DTOs from esi-schema, direct DTO returns

[herpaderpaldent]

Summary

Integrates seatplus/esi-schema as the source of truth for all ESI response DTOs and changes object-endpoint methods to return DTOs directly instead of wrapping them in EsiResult<T>.

Note: This PR is stacked on top of PR #22 (feat/esi-rate-limit-overhaul). Merge that one first.

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What changed

seatplus/esi-schema dependency

• Added "seatplus/esi-schema": "1.x-dev" + VCS repository to composer.json
• src/Generated/Responses/ deleted (218 files removed) — all DTOs now come from esi-schema

Generator (bin/generate.php)

• No longer generates DTO files — resources only
• All DTO use statements changed to Seatplus\EsiSchema\Responses\*

Resource return types

Endpoint type	Before	After
Single object (e.g. getAlliancesAllianceId)	EsiResult<AllianceDetail>	AllianceDetail
Paginated list (e.g. getCharactersCharacterIdAssets)	EsiResult<array<T>>	EsiResult<array<T>> (unchanged)
Primitive array / scalar	EsiResult<T>	EsiResult<T> (unchanged)

Object DTOs extend AbstractEsiDto so $dto->isCachedLoad and $dto->pages are available directly on the returned DTO:

$alliance = $sdk->alliance()->getAlliancesAllianceId(99000006);
echo $alliance->name;        // AllianceDetail — no ->data unwrapping
$alliance->isCachedLoad;     // bool
$alliance->pages;            // int (1 for non-paginated)

README

Added ESI compatibility date notice:

This branch targets ESI compatibility date 2025-12-16 and forward.

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Quality gates

• ✅ Pint: clean
• ✅ PHPStan level 4: 0 errors
• ✅ Pest: 86 passed / 160 assertions

[herpaderpaldent]

Merged directly into #22.