Out-of-tree build layout (since #276) — stale in-repo install/ paths in CLAUDE.md, numeric README, conftest fallback, scripts

[chizamd]

Summary

build.py's default output layout moved out-of-tree in #276 (6f77c6da, "ci(build): from-source dependency resolution + cross-platform build.py"), but a lot of docs/config/test code still assumes the old in-repo install/ layout. The two no longer agree, so paths copied from CLAUDE.md / READMEs / test fallbacks point at directories that build.py never creates.

What changed in #276

Before:

INSTALL = ROOT / "install"          # in-repo: <repo>/install/{dist,therock,...}

After:

REPO = Path(__file__).resolve().parent
WORKSPACE = REPO.parent
--build_dir   default = WORKSPACE/"build"/<repo>     # ../build/<repo>/  (+ _therock, _deps)
--install_dir default = WORKSPACE/"install"          # ../install/      (siblings of the repo)

And TheRock auto-download lands under the build tree: cmake/deps.cmake → _therock_root = ${CMAKE_BINARY_DIR}/_therock = ../build/<repo>/_therock, never <repo>/install/therock.

#276 updated docs/quick_start.md / docs/quick_start_linux.md, but did not sweep the rest of the tree.

Stale in-repo install/... references that no longer match a default build

• CLAUDE.md — the "Output layout" list (install/therock/, install/dist/), and multiple gotchas hardcode install/therock/bin / install/dist/bin on PATH (e.g. the TheRock-DLLs-on-PATH gotcha, the model_benchmark.exe env-var example, the "both bin dirs on PATH" note, the HIPDNN_EP_PERF example).
• test/numeric/README.md — export THEROCK_DIST=$PWD/install/therock, --ep-dll ../../install/dist/bin/....
• test/python/conftest.py — _ep_runtime_dirs() fallbacks are <repo>/install/dist/bin and <repo>/install/therock/bin. With the new default build these dirs don't exist, so the env-var overrides (MORPHIZEN_EP_BIN, THEROCK_DIST) are effectively mandatory, not optional — the legacy fallback is dead.
• test/python/whisper/whisper_infer.py — error string points users at install/dist/bin/onnxruntime_morphizen_ep.dll.
• scripts/transcribe_whisper.py — docstring references install/dist/bin/....

(The Whisper quick-start docs/whisper_quick_start.md was already migrated to a single $ROOT layout + MORPHIZEN_EP_BIN in #283/#266, so it's consistent — this issue is about the rest of the repo.)

Why it's confusing / what breaks

A new user runs the default python build.py (artifacts go to ../build/<repo>/ + ../install/), then follows a CLAUDE.md gotcha that says "add install/therock/bin to PATH" or sets THEROCK_DIST=install/therock — those paths don't exist, so the EP silently falls back to CPU (or tests skip / segfault). The in-tree numeric README env setup is likewise broken against a default build.

Proposed fix (maintainer decision)

Pick one canonical story and make everything reference it:

1. Sweep CLAUDE.md, test/numeric/README.md, whisper_infer.py, transcribe_whisper.py to the out-of-tree layout (../build/<repo>/_therock, ../install or a $ROOT convention), matching docs/quick_start.md.
2. Decide whether conftest._ep_runtime_dirs() should keep the dead in-repo fallback, point the fallback at the new default (WORKSPACE/build/<repo>/_therock, WORKSPACE/install/...), or just require the env vars.
3. Consider a single documented convention (the $ROOT pattern the Whisper guide uses) so build/run/test paths are derived from one variable instead of hardcoded install/... strings scattered across docs.

Origin: noticed while reconciling conftest._ep_runtime_dirs() against the current build during the Whisper work (#283 / #266).