Add per-session credential read rate limiting

[crossagent-production-app]

Fixes #4

Adds a v0 mock credential-read token bucket per session with default 100 reads/minute and a hard cap of 10,000 reads/minute for creation-time overrides. Excess reads return structured rate_limit_exceeded errors with retry_after_secs and emit audit_events rows that agentkeys usage can display. CLI read now surfaces RATE_LIMIT clearly, agentkeys run retries temporary rate limits up to 3 times, and the daemon MCP wrapper returns structured JSON-RPC error data while recording a local audit line.

Verification:

• cargo check -p agentkeys-mock-server -p agentkeys-core -p agentkeys-cli -p agentkeys-mcp
• cargo test -p agentkeys-mock-server credential_rate_limit -- --nocapture
• cargo test -p agentkeys-cli cmd_run -- --nocapture
• cargo test -p agentkeys-daemon mcp_get_credential -- --nocapture

Change:

• Added per-session credential-read token buckets in the mock server with default and configurable caps.
• Added structured rate-limit propagation through core, CLI, and MCP/daemon paths plus usage-visible audit rows.
• Added rate-limit docs and focused tests for burst, refill, per-session isolation, configurable caps, and audit visibility.
  Objective Evidence:
• cargo check -p agentkeys-mock-server -p agentkeys-core -p agentkeys-cli -p agentkeys-mcp passed.
• cargo test -p agentkeys-mock-server credential_rate_limit -- --nocapture passed: 5 tests.
• cargo test -p agentkeys-cli cmd_run -- --nocapture passed: 7 tests.
• cargo test -p agentkeys-daemon mcp_get_credential -- --nocapture passed: 2 tests.
  Visual Evidence:
• n.a.
  Reviewer:
• @repo Intake Reviewer
  Risks / Not Covered:
• Non-visual backend/CLI task; browser screenshot evidence is not applicable.
• v0.1 TEE worker enforcement remains outside this mock-server/CLI implementation scope.

[crossagent-production-app]

Delivery Evidence Summary

Change:

• Added per-session credential-read token buckets in the mock server with default and configurable caps.
• Added structured rate-limit propagation through core, CLI, and MCP/daemon paths plus usage-visible audit rows.
• Added rate-limit docs and focused tests for burst, refill, per-session isolation, configurable caps, and audit visibility.

Objective Evidence:

• cargo check -p agentkeys-mock-server -p agentkeys-core -p agentkeys-cli -p agentkeys-mcp exit code 0, passed: mock server, core, CLI, and MCP crates compiled
• cargo test -p agentkeys-mock-server credential_rate_limit -- --nocapture exit code 0, passed: 5 rate-limit integration tests passed
• cargo test -p agentkeys-cli cmd_run -- --nocapture exit code 0, passed: 7 cmd_run tests passed
• cargo test -p agentkeys-daemon mcp_get_credential -- --nocapture exit code 0, passed: 2 daemon MCP get_credential tests passed

Visual Evidence:

• n.a.

Reviewer:

• @repo Intake Reviewer

Risks / Not Covered:

• Non-visual backend/CLI task; browser screenshot evidence is not applicable.
• v0.1 TEE worker enforcement remains outside this mock-server/CLI implementation scope.

Generated at: 2026-06-04T12:16:03.919Z