Require patched certifi and bootstrap pip before prep installation
The Python incident advisory calls for pip >=26.2.2 and certifi >=2026.10.19. The install instructions currently begin downloading dependencies with whatever pip and CA bundle the environment already has.
Add the advisory's SHA-256-pinned pip bootstrap before dependency downloads, followed by the certifi upgrade. Use python -m pip consistently so installation uses the bootstrapped interpreter. Document the separate system/Git trust-store update and the limits of certifi for native download extensions, with a link to the cross-ecosystem incident guidance. Neither repository contains a Rust/Node build recipe or lockfile to patch; these changes do not establish that downstream native binaries are fixed.
Validation: all README bash blocks pass bash -n; changed files pass whitespace checks. The hash-pinned bootstrap was already exercised in a disposable environment for the companion Space changes (pip 26.2.1 to 26.2.2, certifi 2026.10.19, pip check passed). No model inference, full dependency-resolution test, or native downloader TLS validation was run. Weights, model/code revision pins, and inference code are unchanged.
Also require certifi >=2026.10.19 in package metadata so normal installs cannot retain an older certifi. pip remains an installer prerequisite rather than a runtime package dependency. The prep wheel built successfully with --no-deps, and its METADATA contains the new certifi requirement. This verifies packaging, not an end-to-end installation or inference run.