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## 1.53.1

**`(fix):`** Client-level global header options (e.g. `option.WithVersion(...)` passed
to the root client constructor) are no longer clobbered by env-var or
`client-default` resolution on every request. Env and client-default
fallbacks are now resolved once at client construction, and per-request
options only override the header when explicitly set. Precedence is:
request-level option > client-level option > env var > client default.