feat(db): type nested include in IncludeOption (#2286)

[viniciusdacal]

Summary

• Add TModels generic parameter to IncludeOption, IncludeResolve, ResolveOneInclude, FindResult, FindOptions, ModelDelegate, TypedGetOptions, TypedListOptions, DatabaseClient, and TransactionClient
• When TModels is provided, nested include keys are validated against the target model's relations and output types reflect nested relation data
• New type utilities: FindModelByTable (bidirectional structural match), FindModelRelations, NestedInclude
• Depth cap at 3 typed nesting levels (matching existing IncludeResolve runtime cap)
• Default TModels falls back to untyped Record<string, unknown> for full backward compatibility

Public API Changes

Type	Change
IncludeOption	New optional TModels and _Depth params (defaulted)
IncludeResolve	New optional TModels param (defaulted)
FindResult	New optional TModels param (defaulted)
FindOptions	New optional TModels param (defaulted)
ModelDelegate	New optional TModels param (defaulted)
FindModelByTable	New export — find model entry by table type
FindModelRelations	New export — extract relations from matched model

All changes are backward compatible — existing code using these types without TModels continues to compile unchanged.

Test Coverage

• Input validation: valid/invalid nested keys at depth 1, 2, and 3 (fallback)
• Output resolution: nested relation data in FindResult, nested select narrowing
• Special cases: self-referencing relations, M2M through-relations, false/undefined exclusion
• Registry paths: manual ModelEntry construction and createRegistry-produced models
• Client chain: DatabaseClient.get(), DatabaseClient.list(), TransactionClient (positive + negative)
• Standalone: FindModelByTable, FindModelRelations with backward compat verification

Phase Review

• Adversarial review: 4 should-fix items found and resolved (test gaps + FindModelRelations never-distribution bug)

Follow-up

• feat(server): thread TModels through entity-layer TypedIncludeOption #2309 — Thread TModels through entity-layer TypedIncludeOption

Closes #2286

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