S00-021: Approve S00-021: independently verified browser OMEMO blocker

Changes:
- Wrote state/evidence/S00-021-review.md recording independent re-checks of the
  executor's remediation for S00-004's interruption ("Agent timed out before
  escalation").
- Reproduced both committed probes unchanged: smoke.mjs exit 0 (SMOKE_PASS,
  631-byte session record byte-for-byte reload) and wasm-unsupported.mjs exit 2
  (wasmFiles 0, native-only prebuilds), matching executor evidence exactly.
- Independently re-queried npm registry: @signalapp/libsignal (browser WASM) E404;
  @signalapp/libsignal-client 0.105.0 (native, AGPL-3.0) exists; confirms the
  browser/worker/WASM + OMEMO2 wire-layer blocker is genuine.
- Audited scope via git: commit 30f7f22 touches only the in-scope ADR
  docs/decisions/0003-crypto-library.md plus workflow metadata; experiments/**
  unchanged; working tree clean. No requirement bypass: S00-004 remains blocked,
  ADR 0003 records the honest blocker and forbids done on persistence+Ratchet alone.

Validation:
- make check: 72 tooling tests OK.
- Both probes reproduced, exit codes and output match evidence.
- Acceptance met: interruption repro row exists for next executor; original not
  declared done via bypass.

Task: S00-021
Reviewer agent: auto-security-5d2ae592b569
Role: security
Action: approve

Task: S00-021
Agent: auto-security-5d2ae592b569
Role: security
Action: review
Status: done

Task title: Устранить прерывание: Проверить browser OMEMO backend

planning/TASK_MATRIX.md

@@ -1,13 +1,13 @@
 # Матрица задач
 
-Generated; state revision **59**. Canonical status: state/tasks.json.
+Generated; state revision **60**. Canonical status: state/tasks.json.
 
 | ID | Этап | Оператор | Reviewer | Статус | Owner | Зависимости | Задача |
 | --- | --- | --- | --- | --- | --- | --- | --- |
 | [S00-001](tasks/S00-001.md) | S00 | orchestrator | security | done | auto-orchestrator-48aab142ecde |  | Утвердить Web-профиль |
 | [S00-002](tasks/S00-002.md) | S00 | orchestrator | security | done | auto-orchestrator-68a05c587e33 | S00-001, S00-011, S00-012 | Выбрать framework и build runtime |
 | [S00-003](tasks/S00-003.md) | S00 | protocol | qa | blocked | auto-protocol-59f4d359b339 | S00-001, S00-002, S00-017, S00-018, S00-019, S00-020 | Проверить XMPP WSS/auth библиотеку |
-| [S00-004](tasks/S00-004.md) | S00 | crypto | security | blocked | auto-crypto-8bf3dcf711b9 | S00-001, S00-002, S00-021 | Проверить browser OMEMO backend |
+| [S00-004](tasks/S00-004.md) | S00 | crypto | security | todo |  | S00-001, S00-002, S00-021 | Проверить browser OMEMO backend |
 | [S00-005](tasks/S00-005.md) | S00 | storage | qa | todo |  | S00-002 | Выбрать IndexedDB wrapper и migration policy |
 | [S00-006](tasks/S00-006.md) | S00 | orchestrator | security | todo |  | S00-002 | Зафиксировать browser/reference matrix |
 | [S00-007](tasks/S00-007.md) | S00 | security | orchestrator | todo |  | S00-004, S00-005 | Утвердить password и crypto unlock модель |
@@ -23,7 +23,7 @@ Generated; state revision **59**. Canonical status: state/tasks.json.
 | [S00-018](tasks/S00-018.md) | S00 | protocol | security | done | auto-protocol-89fe6563092c | S00-001, S00-002, S00-017 | Validate bounded standalone XML ingress for the XMPP candidate |
 | [S00-019](tasks/S00-019.md) | S00 | crypto | security | done | auto-crypto-c68801170fa4 | S00-001, S00-002, S00-017, S00-018 | Validate browser-compatible SCRAM-SHA-512 through a public mechanism API |
 | [S00-020](tasks/S00-020.md) | S00 | ci-cd | qa | in_progress | auto-ci-cd-5a18c8aa1b42 | S00-001, S00-002, S00-017, S00-018, S00-019 | Restore access to the pinned Linux XMPP experiment toolchain |
-| [S00-021](tasks/S00-021.md) | S00 | crypto | security | review | auto-crypto-fcef9b6781bf | S00-001, S00-002 | Устранить прерывание: Проверить browser OMEMO backend |
+| [S00-021](tasks/S00-021.md) | S00 | crypto | security | done | auto-crypto-fcef9b6781bf | S00-001, S00-002 | Устранить прерывание: Проверить browser OMEMO backend |
 | [S00-010](tasks/S00-010.md) | S00 | qa | orchestrator | todo |  | S00-001, S00-002, S00-003, S00-004, S00-005, S00-006, S00-007, S00-008, S00-009 | Gate: Профиль и проверка стека |
 | [S01-001](tasks/S01-001.md) | S01 | orchestrator | security | todo |  | S00-010 | Описать identity/model contracts |
 | [S01-002](tasks/S01-002.md) | S01 | orchestrator | security | todo |  | S00-010, S01-001 | Описать async account context |