Enforce the MVP acceptance, performance, accessibility, and security gate

[codeacme17]

Tracks #1.

Summary

Build and enforce the complete MVP acceptance, performance, accessibility, compatibility, and security release gate across standalone and Codex-hosted surfaces.

Scope

• Encode AC-01 through AC-24 as traceable automated tests where feasible, with explicit manual checks only where host/macOS behavior requires them.
• Build the supported-scale fixture: 25 active Worktrees, unavailable diagnostics, 2,000 Changed Files, and 5,000 refs.
• Gate shell ≤1 second, selected ordinary Worktree ≤2 seconds, full supported snapshot ≤5 seconds, visible external change ≤2 seconds, and loaded UI interactions ≤100 ms on the documented reference machine.
• Verify 2 MiB/20,000-line diff degradation without UI freeze.
• Complete keyboard, visible-focus, target-specific accessible-name, live status, non-color, and focus-retention coverage.
• Add Codex Host Adapter compatibility matrix/smoke automation and standalone parity checks.
• Perform threat tests for loopback binding, token/origin validation, iframe capabilities, message generation, path/ref injection, process spawning, and diagnostic redaction.
• Run multi-process race, external lock, disappearing Worktree, and UnknownOutcome recovery tests.
• Publish a release checklist mapping every acceptance scenario to evidence.

Acceptance criteria

• Every AC-01 through AC-24 row has passing evidence or the MVP cannot release.
• Timing measurements are reproducible and record hardware, macOS, Git, Node, and Codex versions.
• No accessibility requirement relies on color alone or mouse-only interaction.
• No security fixture secret appears in logs, UI errors, or test artifacts.
• Standalone and supported Codex-hosted paths expose the same Git product behavior.
• A Codex compatibility failure degrades to the standalone surface without corrupting native UI state.

Out of scope

• New product capabilities or performance work beyond the documented MVP envelope.

Dependencies

• Prove the Codex sidebar and standalone Host Adapters #4 through Add exact-target navigation and optional Codex provenance #15.

PRD coverage

• AC-01–24 and all non-functional requirements.

Verification

• The release gate itself is the verification; archive the matrix and benchmark results as CI artifacts.