feat(telemetry): enable audit mode for telemetry

[Hweinstock]

Problem

The current CLI does not support audit mode. Audit mode allows customers to inspect the telemetry sent without enabling telemetry.

Solution

• implement a MetricSink that continually appends data to a file.
• audit mode relies on a global config flag that defaults to false.

Tests and Verification

• updated unit tests to cover both sinks and verify that audit respects customer's settings.

> rm -rf ~/.agentcore/telemetry
> agentcore config telemetry.audit true
true 
> cat ~/.agentcore/telemetry/* | jq
{
  "metricName": "cli.command_run",
  "value": 29,
  "attrs": {
    "service.name": "agentcore-cli",
    "service.version": "0.0.0",
    "agentcore-cli.installation_id": "42edb4ee-1d41-42cf-96ab-195b0356e05a",
    "agentcore-cli.session_id": "61670d19-1359-46ab-98f9-226db0638353",
    "os.type": "Linux",
    "os.version": "6.12.94-123.190.amzn2023.x86_64",
    "host.arch": "x64",
    "node.version": "v24.3.0",
    "exit_reason": "success"
  }
}

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 95.02%. Comparing base (21353dd) to head (fb6882e).
⚠️ Report is 2 commits behind head on refactor.

Additional details and impacted files

@@             Coverage Diff              @@
##           refactor    #1858      +/-   ##
============================================
+ Coverage     95.00%   95.02%   +0.01%     
============================================
  Files           161      161              
  Lines          7691     7720      +29     
============================================
+ Hits           7307     7336      +29     
  Misses          384      384              

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[notgitika]

just one issue otherwise LGTM!

[notgitika]

Awesome!

[aidandaly24]

This looks good to me. All makes sense and works well from my manual testing.