why

this PR makes the connected SDK the only HTTP transport

what changed

• removed the worker's direct Gateway/cache HTTP execution & the endpoint helper used by that path
• simplified Gateway & cache setup around the client request adapter, removing transport-selection branches & unused context fields
• removed top-level apiKey & apiUrl from worker initialization. the public TypeScript, Python, & Go constructor options still accept them & resolve them in the SDK

test plan

• schema & actual RPC initialization tests reject the removed fields while accepting client transport, direct-provider models, & custom model references.
• Gateway/cache tests cover client routing, retries, cancellation, cache budgets, & unavailable or disconnected transport without falling back to worker HTTP.
• SDK tests verify public connection options remain accepted & incompatible protocol majors are rejected.
• cross-SDK Chromium tests exercise the final route with the regenerated extension; generated-model & bundled-asset checks verify the artifacts match.

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Summary by cubic

Makes the connected SDK the only HTTP transport for Browserbase Model Gateway and cache requests by removing the worker's direct HTTP execution path.

• Removes the worker's direct Gateway/cache HTTP execution and its endpoint helper, along with top-level apiKey and apiUrl from worker initialization.
• Simplifies Gateway and cache setup around the client request adapter by removing transport-selection branches and unused context fields. Regenerates the Go SDK extension bundle and updates SDK parity checks.
• Public TypeScript, Python, and Go constructor options still accept apiKey and apiUrl and resolve them in the SDK.

Breaking Changes

• Worker protocol now rejects apiKey and apiUrl init options and bumps to protocol 3.0.0, which incompatible clients and workers reject with protocol-major-mismatch.