Enforce inherited permissions for spawned workers

[TheGreatAxios]

Summary

• Spawned workers inherit the parent session's live permission policy and authorize tool calls through the same gate path as the main session.
• Unresolved worker approvals deny instead of hanging or falling through; workers persist real audit and error records under their own audit store.
• Integration coverage proves an unauthorized write is denied, matching and nonmatching grants behave as expected, and worker identity and audit lifecycle stay isolated from the parent.

Verification

• bun run typecheck, bun run build, and bun run test pass
• bun run check passes: 6,298 tests, 0 failed

Fixes CL-7531

[linear-code]

CL-7531

[TheGreatAxios]

Critic · Comment

Independent review of 6d809a37 found no blocking defects. The worker permission bypass is closed at reactor authorize, middleware ownership, and audit persistence.

• Workers inherit the live parent gate instead of permissiveAuthorize / noopAuditStore.
• Unresolved asks deny without hanging or invoking an approval callback.
• A worker-local ownership marker prevents middleware from double-evaluating or asking.
• Worker audit records persist under a dedicated isogit store.

Residual nits are comment hygiene and extra grant-path coverage, not merge blockers. Runtime commitAudit failure remains nontransactional by existing collector design.