docs(auth): record 2026-05-31 401-redirect review + dev/prod symmetry proposal

Reviewed commit 4423f0a5 (generalize 401 redirect to all 4 personas) and
verified production has no coverage gap: the only uncovered storefront page
(/loyalty/join) hits exclusively public, no-auth endpoints that can't 401,
and authenticated storefront pages live under /account/ which is already
covered. Remaining gap is dev/path-based-mode only (/platforms/...) — captured
as a deferred enhancement in docs/proposals/auth-redirect-dev-prod-symmetry.md
with the proposed one-line prefix-strip fix and two open implementation
details. No code shipped this session. mkdocs --strict clean; architecture
validation passed (0 new findings).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

mkdocs.yml

@@ -329,6 +329,7 @@ nav:
       - Module Dependency Redesign: proposals/SESSION_NOTE_2026-02-03_module-dependency-redesign.md
       - Import-002 Cross-Module Deps: proposals/SESSION_NOTE_2026-02-09_import002-cross-module-deps.md
       - Android Terminal Implementation: proposals/android-terminal-implementation.md
+      - Auth-Redirect Dev/Prod Symmetry: proposals/auth-redirect-dev-prod-symmetry.md
       - Backward Compatibility Cleanup: proposals/backward-compatibility-cleanup.md
       - CMS Redesign Alignment: proposals/cms-redesign-alignment.md
       - Decouple Modules: proposals/decouple-modules.md