feat(auth): synchronize sign-in, logout and mode switches across tabs

test(auth): real-browser Account E2E, mobile checks; document Account sign-in

feat(auth): UZUMI Account sign-in behind a default-off flag

docs(platform): record ADR-003 Amendment 1

docs(platform): accept ADR-003 UZUMI Account first slice

release(closure): uzumi 0.4.0 RELEASED and VERIFIED — G-7 re-run PASS, E2, Health pre-flight

evaluation(g1): uzumi 0.4.0 G-1 offline checks with tools r7 PASS (2026-10-03-0.4.0-g1-r7)

fix(evaluation): KUP-047 evaluation sessions at Windows Low integrity (F-42); tools r7

evaluation(g7): uzumi 0.4.0 installed G-7 NOT PASS — S2 succeeded plan-file write (F-42)

release(marketplace): pin uzumi to v0.4.0 (7b5a09b)

release(plugin): publish uzumi v0.4.0 evaluation foundation (KUP-044)

evaluation(g6): uzumi 0.4.0 candidate 3 G-6 PASS — ready for the owner's final confirmation (D-019)

evaluation(heldout): uzumi 0.4.0 candidate 3 H-1 / H-2 measured; KUP-029 VERIFIED

evaluation(g5): uzumi 0.4.0 candidate 3 G-5 PASS (2026-10-02-0.4.0-c3-g5-launch2)

evaluation(g4): candidate 3 G-4 record — regression case count 81/81 ok

evaluation(g4): uzumi 0.4.0 candidate 3 G-4 PASS — NO REGRESSION vs contract-1.1.2-target

evaluation(g3): uzumi 0.4.0 candidate 3 G-3 PASS; KUP-045, KUP-046 VERIFIED

evaluation(g3): uzumi 0.4.0 candidate 3 G-3 round a record (2026-10-02-0.4.0-c3-g3-a)

evaluation(g2): uzumi 0.4.0 candidate 3 G-2 PASS (run 2026-10-02-0.4.0-c3-g2)