[antosubash]

Summary

• LocaleMiddleware._negotiate skips Accept-Language candidates whose weight is q<=0 (RFC 9110 §12.4.2, "not acceptable") or nan, so es;q=0 no longer selects es. A refused regional tag (es-MX;q=0) does not fall back to its primary language either.
• q is read case-insensitively from any parameter position and with spaces around = (es;charset=x;q=0, es; q = 0, es;Q=0), so the refusal can't be missed by parameter order.
• Weights above 1 (including inf) count as 1, so an out-of-range weight cannot outrank an unweighted tag; header order breaks the tie.
• Docs (docs/framework/i18n.md, docs/framework/middleware.md, docs/framework-conventions.md) and CHANGELOG (marked as a behaviour change) updated.

Closes #792

Verification

• Browser-verified against a local stack with en and es enabled (port 8241): 11 Accept-Language header variants, a signed-in admin page, and the language switcher, whose cookie still wins over a header refusing Spanish.
• Console: no errors
• Local CI: make lint, make test-py (7,580 passed, 43 skipped), make test-js (891 passed), make doctor, e2e suite (53 passed) all green
• Verification report: https://claude.ai/artifact/7nZpFvnYzVHBtTgPwxvyET

QA Report

• QA cycle completed (1 iteration, shallow depth)
• 0 bugs found, 0 fixed; 2 P3 observations, both pre-existing gaps in the dormant es catalog (users module has no es.json; some admin nav labels untranslated)
• Categories tested: Happy Path, negative header cases, cookie precedence

Report links are Claude Artifacts and start private — the author can share them
from claude.ai/code/artifacts if reviewers need access.

Test plan

• With SM_I18N_SUPPORTED_LOCALES='["en","es"]', curl -H 'Accept-Language: es;q=0' /users/login renders <html lang="en">
• CI is green

https://claude.ai/code/session_01FXHA3ZicrtZ4C5QPEgxfgq

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[chatgpt-codex-connector]

Codex Review Summary

This comment shows the latest Codex review activity on this pull request.

Review	Status	Commit	Review trigger
🔒 Security Review	✅ Completed 2026-11-04T09:33:08.126566Z	a2d9e02	PR opened

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