S00-019: Approve pinned browser SCRAM-SHA-512 after independent verification

Changes: Accept the bounded SHA-512 experiment and ADR, record independent security findings and review handoff, and retain all browser-runtime, WSS, parent-integration and production limitations.
Validation: Fresh-cache npm ci and browser build pass; 87 focused tests and 10 additional signature, verifier-flag and malformed-first checks pass. Newly installed hashed Scramp oracle verifies all three fixed exchanges. Dependency checks confirm 49 locked entries, 25 installed pins/notices and 340 unchanged Stanza files with matching artifact hashes. Canonical RFC digests and installed oracle notices agree; make check passes 72 tooling tests. Actual browser, WSS/live interoperability and release readiness remain untested.

Task: S00-019
Agent: auto-security-f465a677e48f
Role: security
Action: review
Status: done

Task title: Validate browser-compatible SCRAM-SHA-512 through a public mechanism API

planning/stages/S00.md

@@ -8,7 +8,7 @@
 
 - [S00-001](../tasks/S00-001.md): Утвердить Web-профиль — orchestrator; done.
 - [S00-002](../tasks/S00-002.md): Выбрать framework и build runtime — orchestrator; done.
-- [S00-003](../tasks/S00-003.md): Проверить XMPP WSS/auth библиотеку — protocol; blocked.
+- [S00-003](../tasks/S00-003.md): Проверить XMPP WSS/auth библиотеку — protocol; todo.
 - [S00-004](../tasks/S00-004.md): Проверить browser OMEMO backend — crypto; todo.
 - [S00-005](../tasks/S00-005.md): Выбрать IndexedDB wrapper и migration policy — storage; todo.
 - [S00-006](../tasks/S00-006.md): Зафиксировать browser/reference matrix — orchestrator; todo.
@@ -23,7 +23,7 @@
 - [S00-016](../tasks/S00-016.md): Restore reviewer model availability after provider capacity failure — ci-cd; done.
 - [S00-017](../tasks/S00-017.md): Establish fail-closed SCRAM server-final validation — protocol; done.
 - [S00-018](../tasks/S00-018.md): Validate bounded standalone XML ingress for the XMPP candidate — protocol; done.
-- [S00-019](../tasks/S00-019.md): Validate browser-compatible SCRAM-SHA-512 through a public mechanism API — crypto; review.
+- [S00-019](../tasks/S00-019.md): Validate browser-compatible SCRAM-SHA-512 through a public mechanism API — crypto; done.
 - [S00-010](../tasks/S00-010.md): Gate: Профиль и проверка стека — qa; todo.
 
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