security(core/R-15): Gate 7 — explicit production authority switch, legacy migration and cutover

[qnbs]

Program position

Child owner of #445 for R-15 Gate 7 — the final semantic production cutover.

TARGET_RELEASE = v1.30.0
PREDECESSOR = Gate 6 terminal
CURRENT_AUTHORIZATION = NO
REQUIRES_EXPLICIT_MAINTAINER_AUTHORIZATION = YES

Objective

After Gates 1–6 are terminal and packaged evidence is clean, perform the separately authorized release migration that makes renderer-neutral Rust Core secure storage the authoritative packaged-desktop at-rest path. Browser/PWA remains independent.

Preconditions

• security(core/R-15): renderer-neutral encrypted desktop storage, durable migration & identity binding #445 Gates 1–6 terminal;
• Desktop atomic writes: fsync temp file + parent directory before/after rename for true crash durability #357/Desktop fs-data key-rotation migration is not crash-resumable (mixed-key state possible) #359/Desktop fs reads/writes don't participate in the encryption-migration admission lock (race window during disable/rotate) #360/Bind desktop fs-backed ciphertext to its record identity (AAD) to prevent cross-file substitution #361 reconciled;
• every packaged PROTECTED class has a migration/refusal result;
• packaged Linux/Windows/macOS evidence from Gate 6;
• rollback/recovery plan proven;
• no unresolved P0/P1 on cutover path;
• release/security truth docs prepared but not prematurely published;
• explicit maintainer approval recorded to change PRODUCTION_AUTHORITY_SWITCH_ALLOWED from NO.

Cutover requirements

• route all packaged-desktop protected readers/writers through Core authority;
• replace filename/directory-trusting enumeration with authenticated list_records/record catalog where contract requires;
• preserve-first legacy migration;
• retain recoverable prior source until target durable verification permits cleanup;
• forbid silent fallback to old plaintext/legacy writers;
• explicit recovery/downgrade semantics;
• truthful UI/runtime locked/recovery states;
• preserve data through restart/crash/rollback boundaries.

Acceptance

• packaged upgrades from supported prior versions;
• every protected class encrypted at rest or explicitly retained under an approved separate protected authority;
• no plaintext authoritative siblings/remnants outside approved recovery/retention;
• exact artifact qualification on supported desktop platforms;
• rollback/recovery drills;
• security/privacy/docs claims match observed product truth;
• only then R-15 production authority may be declared terminal.

This issue must never self-authorize the switch.

[qnbs]

Linear control-plane mirror

• Linear: QNB-171
• Project: v1.30.0 — Complete Desktop At-Rest Encryption
• Project URL: https://linear.app/qnbs/project/v1300-complete-desktop-at-rest-encryption-1ea741fa2ae5

GitHub remains the implementation/evidence source of truth; Linear tracks sequencing, priority, dependencies and milestone progress.