Fix organization profile images in GitHub Mobile

[VolkerChristian]

Organization-profile images use README-relative URLs, which GitHub Mobile can resolve from the repository root instead of profile/. Public and member views therefore show broken banners/buttons despite valid published assets. Use absolute URLs to the authoritative public assets for every profile image src and picture srcset, including mobile and dark variants. The existing member-profile sync copies the corrected generated README.

The menu generator resolves those profile-owned URLs back to local assets while retaining the original URL in the HTML. Consolidate path/URI rejection at the existing ownership guard; foreign URLs and filesystem-absolute paths remain excluded. No new publishing mechanism, renderer, image copy or configuration flag is added.

Files

• profile/template.md: eight explicit public asset URLs and the authoring rule.
• profile/README.md: regenerated with snodec_sync profile.
• tools/snodec_sync/navigation.py: preserve local menu generation for the canonical profile URLs.
• tests/test_sync.py: every image URL must be absolute, public and backed by an owned local file.
• tests/test_navigation.py: verify button/HTML width normalization, URL preservation, foreign-URL exclusion and no drift.

Verification

• python tools/snodec_sync check — PASS.
• python tools/snodec_sync profile then git diff --exit-code profile/README.md — PASS after commit, no drift.
• python -m unittest discover -s tests -v — 74 tests passed (10.868 s).
• python tools/snodec_sync page-headers --repo . --check — PASS.
• python tools/snodec_sync docs-audit --repo . — 0 violations.
• git diff --check HEAD^ HEAD — PASS.
• Central header checks for snode.c, mqttsuite, AISuite, CodexUI, DistributionPackages and DistributionPackages/site — PASS, no changes.
• All eight full public image URLs return HTTP 200 / image/svg+xml; public/member assets have identical blob hashes. Baseline browser checks at phone/tablet/desktop widths load all selected images.

Production Python: +3/-4 lines (net -1). Test Python: +21/-3 lines. No SVG, license, historical record, workflow definition, tag or setting changes. Native GitHub-app behavior cannot be directly verified on a device in this environment; this corrects the URL-resolution boundary matching GitHub's acknowledged organization-profile issue.

The owner authorized merge and live publication. On merging, existing main validation requests the member-profile sync. No product or package build workflow is needed or requested.