feat(generator): build full SDK generation foundation

[nmorgan-cb]

Description

Builds the deterministic, OpenAPI-driven generation foundation for the full Coinbase Prime Java client surface.

Generator implementation included

• Uses the committed apiSpec/prime-public-spec.yaml for normal generation and CI; live fetching is explicit and non-mutating.
• Runs raw OpenAPI model/enum generation and the existing post-processing before custom client-surface emission.
• Adds shared paths, configuration, naming/type resolution, request, response, service, factory, template, manifest, and reconciliation phases.
• Generates SDK-style mutable request/response DTOs, synchronous services/implementations, and PrimeServiceFactory deterministically.
• Preserves Java compatibility for request builders, pagination, primitive booleans, status handling, /v1 and per-call /v2 routing, service/method aliases, PrimeXM* naming, and existing model transformations.
• Routes OpenAPI *ErrorCode and *Subcode enums into com.coinbase.prime.model.errors, aligned with the .NET generator architecture.
• Provides make fetch-spec, make generate, make check-generated, and make generate-live-diff. Check and live-diff modes render/format only in isolated temporary locations and never mutate the checkout.

Tests added

• Adds focused coverage for parsing, naming/type resolution, configuration/overrides, request/response/service/factory rendering, status compatibility, version routing, error-enum generation, safe stale cleanup, protected compatibility drift, and non-mutating checks.
• Generator suite: 29 tests; root SDK suite: 285 tests.

Generation preview performed

• Ran full generation in detached temporary worktrees using the committed spec, then compiled, tested, and Spotless-checked the generated SDK successfully.
• The final preview reports 597 intentionally uncommitted baseline changes, including 336 generated error enums.
• Also verified .NET PR chore: Fix generation of javadoc comments #3 locally (dotnet test: 60 generator tests and 18 SDK tests) and incorporated its naming/error-enum conventions where compatible with established Java public APIs.

Generated SDK baseline intentionally not committed

No regenerated model, DTO, service, factory, error-enum, spec, or manifest artifacts are included in this PR. Generated output will be committed only after the baseline is reviewed.

Remaining follow-up

Review and commit the generated SDK baseline, then enable make check-generated as a required CI gate.

Generated with Toshi

Type of Change

• Bug fix
• New feature
• Breaking change
• Dependency update
• Refactor / cleanup
• Other (describe below)

Checklist

• Tests included / updated
• Changelog updated
• Version bump if needed

[cb-heimdall]

🟡 Heimdall Review Status

Requirement	Status	More Info
Reviews	🟡 0/1	Denominator calculation Show calculation 1 if user is bot 0 1 if user is external 0 2 if repo is sensitive 0 From .codeflow.yml 1 Additional review requirements Show calculation Max 0 0 From CODEOWNERS 0 Global minimum 0 Max 1 1 1 if commit is unverified 0 Sum 1