v1.36.276

Reuse a native Git location on Windows only while the caller environment, resolved working directory and inspected PATH candidate files remain unchanged. A changed or unreadable path falls back to the original system where.exe lookup; shell-free execution and cwd-shadow rejection remain in place.

Add a Windows regression check for unchanged, inserted, replaced and removed Git candidates, environment changes, cwd shadows, junction retargeting and caller mutation to the runtime tier. A measured publication case fell from 225 to 117 seconds with the same 1,579 Git commands; full-suite results are tracked separately.