fix(opencode): revert google sdk tool call id change

[rekram1-node]

Summary

• revert the direct @ai-sdk/google pin from 3.0.75 to 3.0.63 in opencode and core
• retain @ai-sdk/google-vertex@4.0.131 and its nested Google SDK update
• refresh bun.lock to isolate the rollback to the non-Vertex Google path

Context

@ai-sdk/google@3.0.74+ replays Gemini function calls with functionCall.id and matching functionResponse.id. This works against Google directly, but Zen-routed opencode/gemini-3.1-pro requests hitting a managed GCP /v1 connection fail after the first tool call with HTTP 400:

Invalid JSON payload received. Unknown name "id" at contents[1].parts[1].function_call
Invalid JSON payload received. Unknown name "id" at contents[2].parts[0].function_response

This rolls back the direct Google SDK path while preserving the Google Vertex thought-signature update.

Verification

• bun install --lockfile-only
• git diff --check
• bun typecheck in packages/opencode
• bun typecheck in packages/core