* Studio RAG: disable trust_env on loopback llama-server httpx clients
The RAG embedder health probe (embed_llama_server.py), its pooled httpx.Client, and the vision captioner (captioner.py) call the local 127.0.0.1 llama-server with httpx's default trust_env=True, so an ambient HTTP(S)_PROXY that returns 503 for loopback breaks embedder startup and captioning. Set trust_env=False on these loopback clients, matching the existing fix on the main llama_cpp and inference clients. External provider calls are untouched.
Follow-up to the loopback trust_env fix; covers the remaining local llama-server clients in the RAG path.
* [pre-commit.ci] auto fixes from pre-commit.com hooks
for more information, see https://pre-commit.ci
* Studio RAG tests: accept trust_env kwarg in captioner httpx.post mocks
The loopback captioner now passes trust_env=False; update the _vision_complete
fake_post stubs to accept it and assert it is False.
* Trim comments in Studio RAG trust_env fix (comment-only)
* RAG trust_env test: explicit UTF-8 read + scan all package .py files
Addresses review: utf-8 open avoids a Windows decode error, and scanning every
.py in core/rag catches any future file that adds an httpx call.
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Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>
