feat(api): enforce durable request budgets and refusal stops #15

[yashiels]

Summary

• Route authenticated API traffic through durable, host-user-wide request admissions: minimum 5-second spacing, at most 100 admissions per rolling 24 hours, and one in-flight exchange.
• Preserve spacing independently of quota-history pruning, including configured delays longer than 24 hours and fresh-process restarts.
• Persist cooldowns and manual-review refusal stops before response-body decoding; do not automatically retry application requests.
• Add local safety status/resume commands and allowlisted diagnostics that preserve safe numeric HTTP status without exposing raw response/error content.
• Fail closed on unsafe state, ownership, modes and native ACLs. Native Linux access/default ACL tests include unchanged denied state and a successful control after removing only the injected fixture ACL.

Depends on merged #17. Documentation/release follow separately under #16.

Verification

• Reviewed head: 054b6ef4590a94672a8f471ef0f67394a9c290fa.
• Both signed commits verified; the published parent was preserved and the review fix added without force-push. Squash merge yields one landed M2 commit.
• Independent macOS make ci, make lint, scratch build and offline CLI smoke passed using isolated fixture state and no account credentials.
• Actual unchanged Linux workflow executed with act: vet, race tests and gofmt all passed. All 10 packages were present, including the command package; both native ACL cases passed.
• Pinned tracked-source export verified before and after execution: all 86 paths, Git blob identities and executable modes matched the reviewed tree.
• Separate state and API/CLI reviews signed off; subsequent deltas, including the final production fixes, also signed off on this exact head.
• Late inline findings fixed and regression-tested: ordinary profile failures stop immediately, only the deprecated REST endpoint can fall back on HTTP 410, and valid auth redirects with literal-percent suffixes persist the manual-review stop across fresh clients/policies.
• No live LinkedIn/employer traffic, saved credential replacement or real refusal reset performed.

Limits

• This budget counts application admissions, not exact physical packets. Restricted standard-transport connection recovery and trusted custom-transport internals remain outside exact wire-attempt accounting.
• These thresholds are operational safeguards, not LinkedIn-approved limits or protection against account restrictions.
• Host-local state does not coordinate other hosts, older binaries or unrelated applications.
• The full-source archive CI invocation disables act Git-ignore filtering so an ignored binary basename cannot omit the tracked command source directory. No workflow checks were weakened.

Closes #15

[sentinel-skyner]

🛡️ Sentinel review

Two policy gaps allow unintended follow-up admissions.

2 inline comments below.

_{Automated review via cursorbridge:gpt-5.6-sol. Findings only — not an approval. Push new commits to re-review.}

[sentinel-skyner]

🛡️ Sentinel review

No material issues found in the reviewed diff.

_{Automated review via cursorbridge:gpt-5.6-sol. Findings only — not an approval. Push new commits to re-review.}