## Why
Make it possible to load AGENTS.md from remote exec-servers whose OS is
different than app-server.
## What
- keep `AGENTS.md` discovery and provenance as `PathUri`, with
root-aware parent and ancestor traversal
- expose lifecycle instruction sources as legacy app-server path strings
in events while retaining `PathUri` internally
- preserve and test mixed POSIX and Windows paths in model context and
TUI status output
- cover remote Windows loading end to end by seeding the Wine prefix
through host filesystem APIs
- fix bug in `PathUri`'s parent() implementation that would erase
Windows drive letters
## Why
We want to exercise a linux app-server against a windows exec-server
without having to repeat every test case. This approach has slight
precedent in the remote docker test setup.
## What
Run the shared `codex-core` integration suite against Windows
exec-server behavior from Linux. This makes cross-OS path and shell
regressions visible while keeping unsupported cases owned by individual
tests.
- Add `local`, `docker`, and `wine-exec` test environment selection with
legacy Docker compatibility.
- Extend `codex_rust_crate` to generate a sharded Wine-exec variant
using a cross-built Windows server and pinned Bazel Wine/PowerShell
runtimes.
- Teach remote-aware helpers about Windows paths and track temporary
incompatibilities with source-local `skip_if_wine_exec!` calls and
follow-up reasons.
