fix: remove footer from the branding

[antosubash]

Closes#273

Headless Pi worker

This is a draft pull request created from an issue carrying the approval label.
It is never merged automatically and requires human review.

Agent summary

Summary

• Removed configurable footer ownership from the branding module, including API routes, settings, contracts, shared props, editor components, and localization keys.
• Restored framework-owned footer rendering in site layouts.
• Updated branding documentation and added regression coverage confirming footer routes return 404.

Changed areas

• modules/branding/
• packages/ui/
• Generated packages/i18n/src/*
• Branding documentation

Verification

• uv run --all-packages pytest modules/branding/tests — 114 passed
• npx vitest run packages/ui/src/components/BrandingFooter.test.tsx — 3 passed
• make lint — passed
• uv run --all-packages python -m simple_module_core — 0 errors, one unrelated existing SM003 AuditLog warning
• git diff --check — passed

Evidence / risks

• Visual evidence: none.
• Existing persisted footer setting rows are left inert rather than destructively deleted.
• No blockers.

Local visual evidence

When requested, screenshots, traces, videos, and GIFs are stored only under the worker worktree's ignored
.qa/issues/273/ directory. GitHub CLI cannot attach those files; inspect them on the worker host
or attach selected evidence manually.

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View logs

[antosubash]

/pi review

[antosubash]

✅ Feedback processed with no tracked code changes.

• Feedback:/pi review requested a review but contained no actionable change request.
• Response: Inspected the implementation; no additional changes were needed. Worktree remains clean.

Checks

• Branding tests: 20 passed
• BrandingFooter tests: 3 passed
• Ruff and Biome checks: passed
• git diff --check: passed

Evidence: None required.
Blockers: No substantive maintainer feedback was provided to address.