feat(copy): fix Python SDK starter and polling examples

[runshouse]

Add required image_count=1, use check_result(id=project_id, ...), and download into the existing current directory in the root README. Generator/editor resource examples explicitly use Free-compatible z-image-turbo / flux-2-klein at 640px, with both response cost aliases matching the source-derived 5-credit single output. Sync and async upload docstrings now supply required top-level scale_factor=2, not unsupported style.upscale_factor. Four custom generator/editor docstring sentences now describe model/resolution-dependent pricing instead of falsely promising every request costs5 credits. Face Editor sync/async samples use supported values in increments of 5, not rejected fractional values. Omitted runtime defaults, entitlements and prices remain unchanged.

On devbox, 169 existing Python3.12 tests passed in 30.64 seconds after the Face Editor update; mypy over 241 source files, existing parameter-sync and whitespace checks passed. Changed README formatting passed; docstring substitutions preserve existing Python formatting. Source review verifies current methods/types/required fields and canonical model/resolution price counterexamples. Earlier corrected root methods and saved-ID wiring ran against the existing Sideko mock with a dummy token and wait/download disabled. Existing checks do not extract README/docstring examples or prove real generation, files, billing or quality. Documentation-only, including existing sync/async docstrings; no runtime, tests, manifests or dependency changes. Updated HEAD f98f72b56898fbf0dc35d62e019691dc875d16be; native Python3.10-3.13 and parameter-sync checks passed at this HEAD.