feat: add Codex Apps sediment file remapping (#15197)

## Summary
- bridge Codex Apps tools that declare `_meta["openai/fileParams"]`
through the OpenAI file upload flow
- mask those file params in model-visible tool schemas so the model
provides absolute local file paths instead of raw file payload objects
- rewrite those local file path arguments client-side into
`ProvidedFilePayload`-shaped objects before the normal MCP tool call

## Details
- applies to scalar and array file params declared in
`openai/fileParams`
- Codex uploads local files directly to the backend and uses the
uploaded file metadata to build the MCP tool arguments locally
- this PR is input-only

## Verification
- `just fmt`
- `cargo test -p codex-core mcp_tool_call -- --nocapture`

---------

Co-authored-by: Codex <noreply@openai.com>

codex-rs/Cargo.lock

@@ -1414,6 +1414,7 @@ dependencies = [
  "reqwest",
  "serde",
  "serde_json",
+ "tempfile",
  "thiserror 2.0.18",
  "tokio",
  "tokio-test",