feat: add first-class Bedrock Runtime support (SDK-290)

[HAYDEN-OAI]

Summary

• Add first-class BedrockEndpoint.RUNTIME support to the existing optional openai-java-bedrock artifact and idiomatic BedrockOpenAIOkHttpClient.builder().endpoint(...), while preserving Mantle as the default.
• Derive partition-aware Runtime endpoints, infer Runtime from canonical standard/FIPS/dual-stack endpoint overrides, validate canonical HTTPS, endpoint-family and region agreement, and require explicit endpoint selection before signing custom proxy URLs.
• Sign Runtime requests with AWS SigV4 service bedrock; preserve bearer-token authentication, default AWS credentials, named profiles, refreshable providers, static/session credentials, credential precedence, per-attempt refresh/re-signing, redirects, origin isolation, and secret redaction.
• Add WireMock and unit coverage for synchronous/asynchronous Chat Completions, Responses, bearer/SigV4 streaming, retries, seven AWS partitions, malformed-region injection, and Sol/Terra/Luna inference profiles.
• Document Runtime selection, model IDs, route overrides, stale environment bearer tokens, and deployment-dependent API availability in bedrock.md; add a runnable Chat/streaming example and an opt-in live inference-profile matrix.

Why

Implements the Java workstream for SDK-290 with endpoint and authentication behavior aligned with the Node reference implementation in openai/openai-node#2348. Runtime targets bedrock-runtime.<region>.<partition-suffix> and signs with bedrock, whereas the existing Mantle endpoint signs with bedrock-mantle.

Verification

• ./gradlew :openai-java-bedrock:compileKotlin :openai-java-bedrock:compileTestKotlin :openai-java-example:compileJava
• ./gradlew :openai-java-bedrock:format :openai-java-example:format
• ./gradlew :openai-java-bedrock:test :openai-java-bedrock:lint :openai-java-example:compileJava :openai-java-example:lint
• Focused results: 43 tests passed, 0 failed; the single credentialed live test is intentionally skipped unless BEDROCK_LIVE_TEST=1 is set.

Compatibility and rollout

• Existing Mantle clients retain their current default endpoint and signing service.
• Canonical AWS overrides infer their endpoint family; a custom signed proxy now requires explicitly selecting BedrockEndpoint.MANTLE or BedrockEndpoint.RUNTIME so its SigV4 service cannot be ambiguous.
• Runtime model access, bearer acceptance, Responses availability, and streaming support remain AWS account/model/deployment-dependent; no credentialed live AWS requests were executed as part of this verification.
• AWS dependencies remain isolated to openai-java-bedrock; generated README files are unchanged.

[openai-sdks]

OkTest Summary

✅ 237/237 SDK tests passed in 16.689s for Java SDK PR #866.

Test results — 42 files

Test	Result	Time
tests/chat-completions-complex-body.test.ts	✅ Passed	662ms
tests/chat-completions-create.test.ts	✅ Passed	504ms
tests/chat-completions-stream.test.ts	✅ Passed	490ms
tests/files-content-binary.test.ts	✅ Passed	197ms
tests/files-create-multipart.test.ts	✅ Passed	260ms
tests/files-list-pagination.test.ts	✅ Passed	289ms
tests/initialize-config.test.ts	✅ Passed	201ms
tests/instance-isolation.test.ts	✅ Passed	185ms
tests/models-list.test.ts	✅ Passed	219ms
tests/responses-background-lifecycle.test.ts	✅ Passed	552ms
tests/responses-body-method-errors.test.ts	✅ Passed	638ms
tests/responses-cancel-timeout.test.ts	✅ Passed	235ms
tests/responses-cancel.test.ts	✅ Passed	386ms
tests/responses-compact-retries.test.ts	✅ Passed	527ms
tests/responses-compact.test.ts	✅ Passed	292ms
tests/responses-create-advanced-stream.test.ts	✅ Passed	376ms
tests/responses-create-advanced.test.ts	✅ Passed	1.359s
tests/responses-create-disconnect.test.ts	✅ Passed	1.124s
tests/responses-create-errors.test.ts	✅ Passed	443ms
tests/responses-create-malformed-api-responses.test.ts	✅ Passed	339ms
tests/responses-create-retries.test.ts	✅ Passed	247ms
tests/responses-create-stream-failures.test.ts	✅ Passed	211ms
tests/responses-create-stream-timeout.test.ts	✅ Passed	246ms
tests/responses-create-stream-wire.test.ts	✅ Passed	6.346s
tests/responses-create-stream.test.ts	✅ Passed	494ms
tests/responses-create-terminal-states.test.ts	✅ Passed	377ms
tests/responses-create-timeout.test.ts	✅ Passed	259ms
tests/responses-create.test.ts	✅ Passed	268ms
tests/responses-delete.test.ts	✅ Passed	320ms
tests/responses-input-items-errors.test.ts	✅ Passed	276ms
tests/responses-input-items-list.test.ts	✅ Passed	376ms
tests/responses-input-items-options.test.ts	✅ Passed	521ms
tests/responses-input-tokens-count-timeout.test.ts	✅ Passed	265ms
tests/responses-input-tokens-count.test.ts	✅ Passed	360ms
tests/responses-malformed-inputs.test.ts	✅ Passed	5.11s
tests/responses-not-found-errors.test.ts	✅ Passed	374ms
tests/responses-parse.test.ts	✅ Passed	614ms
tests/responses-retrieve-retries.test.ts	✅ Passed	287ms
tests/responses-retrieve.test.ts	✅ Passed	305ms
tests/responses-stored-method-errors.test.ts	✅ Passed	971ms
tests/retry-behavior.test.ts	✅ Passed	3.368s
tests/sdk-error-shape.test.ts	✅ Passed	415ms

View OkTest run #31912756882

_{SDK merge (9410711c9ae0) · head (56d8ab79a310) · base (fcdcc7ee0414) · OkTest (7e7850017529)}

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