Fix Windows Cookbook background tasks, exit statuses, and empty SSH logs wrapper (#1389)

This commit consolidates all Windows Cookbook background fixes into a single comprehensive commit based on the latest main branch.

Key fixes included:
1. React looksSuccessful Mismatch: Append 'DOWNLOAD_OK' for pip install commands in routes/cookbook_routes.py.
2. Local Windows SSH Wrapper & Log Directory Mismatch: Bypassed ssh wrappers and dynamically selected odysseus-tmux logs for local tasks in static/js/cookbookRunning.js.
3. WSL Bash Filtration: Filtered out the WSL bash stub at C:\Windows\System32\bash.exe in core/platform_compat.py.
4. Drive-Colon Path Normalization: Replaced .as_posix() with git_bash_path() in routes/shell_routes.py and src/bg_jobs.py.
5. GGUF-Only Hardware Fitting: Restructured local Windows recommendations to rank GGUF only in services/hwfit/fit.py.
6. Safe Win32 Process Liveness Probe: Replaced os.kill(pid, 0) with a safe Win32 API probe using GetExitCodeProcess in core/platform_compat.py.
7. Prebuilt llama-cpp-python Wheels: Supply the CPU extra index during compilation failure fallback.
8. Enforce UTF-8 log encoding: Set PYTHONIOENCODING=utf-8 on Windows bootstrap runners.
9. Fix Linux Llama.cpp Build script syntax error in routes/cookbook_helpers.py.
10. Page Reload Status Check: Run sys.executable instead of 'python3' to bypass Microsoft Store execution stubs on local Windows hosts.
11. Llama.cpp serve build bypass: Bypassed cmake compilation checks on local Windows and verified python bindings directly.
12. Serve Command Path Validation: Masked safe GGUF path printf subshells '' inside the serve command validator.
13. CPU Mismatch Diagnostics: Intercepted AVX2-lacking '0xc000001d' (Illegal Instruction) crashes in static/js/cookbook-diagnosis.js and guided users to Ollama.
14. Windows Pytest stability: Fixed stub import leakage in test files.

routes/cookbook_helpers.py

@@ -206,12 +206,16 @@ def _pip_install_fallback_chain(package: str, *, python_cmd: str = "python3 -m p
     exit code is preserved (no ``| tail`` masking) and the last 5 lines of
     pip output appear in the Cookbook log on failure.
     """
+    from core.platform_compat import IS_WINDOWS
     upgrade_flag = " -U" if upgrade else ""
     # Shell-quote the package spec: an extras spec like ``llama-cpp-python[server]``
     # contains brackets that bash would treat as a glob, so it must be quoted
     # before being embedded in the install command. Plain names (e.g.
     # ``huggingface_hub``) are returned unchanged by ``shlex.quote``.
     pkg = shlex.quote(package)
+    if IS_WINDOWS and "llama-cpp-python" in package:
+        pkg += " --extra-index-url https://abetlen.github.io/llama-cpp-python/whl/cpu"
+
     base = _pip_install_attempt(f"{python_cmd} install -q{upgrade_flag} {pkg}")
     user = _pip_install_attempt(f"{python_cmd} install --user --break-system-packages -q{upgrade_flag} {pkg}")
     # Derive the python executable for the venv detection check.
@@ -525,6 +529,7 @@ def _validate_serve_cmd(v: str | None) -> str | None:
     # Backticks and raw newlines are never legitimate here.
     if any(c in v for c in ("`", "\n", "\r")):
         raise HTTPException(400, "Invalid characters in cmd")
+
     # Known GGUF launcher prelude → validate the serve invocation(s) it guards.
     m = _GGUF_PRELUDE_RE.match(v)
     if m:
@@ -533,9 +538,19 @@ def _validate_serve_cmd(v: str | None) -> str | None:
         for part in rest.split("||"):
             _check_serve_binary(part.strip())
         return v
+
     # Otherwise: a single invocation — no shell metacharacters allowed.
+    # Temporarily replace safe $(printf %s ...) expressions with a placeholder
+    # to avoid triggering the metacharacter/command-injection checks.
+    cleaned_v = v
+    printf_matches = list(re.finditer(r"\$\(\s*printf\s+%s\s+([^\n()]*?)\)", v))
+    for match in printf_matches:
+        inner = match.group(1)
+        if not any(c in inner for c in (";", "&&", "||", "$(", "`")):
+            cleaned_v = cleaned_v.replace(match.group(0), "/placeholder/safe/path.gguf")
+
     # (`$(` was the original intent; bare `$` is fine for shell-safe paths.)
-    if any(c in v for c in (";", "&&", "||", "$(")):
+    if any(c in cleaned_v for c in (";", "&&", "||", "$(")):
         raise HTTPException(400, "Invalid characters in cmd")
     _check_serve_binary(v)
     return v