fix(azure): encode deployment names consistently

[apcha-oai]

Azure requests that select a deployment through model should handle its name consistently with other SDK path parameters. Use the existing path encoder when constructing the deployment URL, preserving the selected operation and normal deployment names.

Fixed-deployment clients and non-deployment endpoints retain their existing routing behavior. Includes focused synchronous and asynchronous regression coverage.

[openai-sdks]

OkTest Summary

✅ 237/237 SDK tests passed in 11.179s for Python SDK PR #3683.

Test results — 42 files

Test	Result	Time
tests/chat-completions-complex-body.test.ts	✅ Passed	201ms
tests/chat-completions-create.test.ts	✅ Passed	229ms
tests/chat-completions-stream.test.ts	✅ Passed	138ms
tests/files-content-binary.test.ts	✅ Passed	243ms
tests/files-create-multipart.test.ts	✅ Passed	227ms
tests/files-list-pagination.test.ts	✅ Passed	155ms
tests/initialize-config.test.ts	✅ Passed	174ms
tests/instance-isolation.test.ts	✅ Passed	181ms
tests/models-list.test.ts	✅ Passed	215ms
tests/responses-background-lifecycle.test.ts	✅ Passed	248ms
tests/responses-body-method-errors.test.ts	✅ Passed	289ms
tests/responses-cancel-timeout.test.ts	✅ Passed	202ms
tests/responses-cancel.test.ts	✅ Passed	200ms
tests/responses-compact-retries.test.ts	✅ Passed	323ms
tests/responses-compact.test.ts	✅ Passed	332ms
tests/responses-create-advanced-stream.test.ts	✅ Passed	133ms
tests/responses-create-advanced.test.ts	✅ Passed	215ms
tests/responses-create-disconnect.test.ts	✅ Passed	1.206s
tests/responses-create-errors.test.ts	✅ Passed	201ms
tests/responses-create-malformed-api-responses.test.ts	✅ Passed	320ms
tests/responses-create-retries.test.ts	✅ Passed	320ms
tests/responses-create-stream-failures.test.ts	✅ Passed	136ms
tests/responses-create-stream-timeout.test.ts	✅ Passed	212ms
tests/responses-create-stream-wire.test.ts	✅ Passed	3.686s
tests/responses-create-stream.test.ts	✅ Passed	82ms
tests/responses-create-terminal-states.test.ts	✅ Passed	237ms
tests/responses-create-timeout.test.ts	✅ Passed	238ms
tests/responses-create.test.ts	✅ Passed	254ms
tests/responses-delete.test.ts	✅ Passed	234ms
tests/responses-input-items-errors.test.ts	✅ Passed	413ms
tests/responses-input-items-list.test.ts	✅ Passed	301ms
tests/responses-input-items-options.test.ts	✅ Passed	324ms
tests/responses-input-tokens-count-timeout.test.ts	✅ Passed	224ms
tests/responses-input-tokens-count.test.ts	✅ Passed	209ms
tests/responses-malformed-inputs.test.ts	✅ Passed	2.798s
tests/responses-not-found-errors.test.ts	✅ Passed	255ms
tests/responses-parse.test.ts	✅ Passed	388ms
tests/responses-retrieve-retries.test.ts	✅ Passed	297ms
tests/responses-retrieve.test.ts	✅ Passed	196ms
tests/responses-stored-method-errors.test.ts	✅ Passed	607ms
tests/retry-behavior.test.ts	✅ Passed	3.301s
tests/sdk-error-shape.test.ts	✅ Passed	266ms

View OkTest run #32298470925

_{SDK merge (630904e67c4a) · head (a4e6eeaad53e) · base (1fc0a217047c) · OkTest (2b1bdfd25e98)}

[jbeckwith-oai]

Independent two-pass security review confirms Azure deployment names remain confined to one canonical URL path segment across synchronous and asynchronous clients. Separators, encoded traversal, query/fragment delimiters, controls, and Unicode are handled safely without changing fixed-deployment routing, authentication, streaming, or realtime behavior. Focused tests and substantive CI are green; no actionable findings.