feat(telemetry): print a post-command notice on first run

[Hweinstock]

Problem

We are missing the post-first run telemetry notice on the refactor branch.

Solution

• avoid writing the installationId as a side effect within globalConfig.
• at the top level, determine if its the firstRun by checking if installationId is there, otherwise attempt to persist one.
• print a telemetry notice when installationId was not there, and telemetry is enabled

Verification

> rm ~/.agentcore/config.json
> agentcore config 
{
  "telemetry": {
    "enabled": true,
    "audit": false,
    "endpoint": "https://telemetry.agentcore.aws.dev"
  },
  "installationId": "e92dbb9b-cd4f-4b9f-94cc-ef69d95087cb"
}

The AgentCore CLI collects aggregated, anonymous usage analytics to help improve the tool.
To opt out:   agentcore config telemetry.enabled false
To audit:     agentcore config telemetry.audit true
> agentcore config 
{
  "telemetry": {
    "enabled": true,
    "audit": false,
    "endpoint": "https://telemetry.agentcore.aws.dev"
  },
  "installationId": "e92dbb9b-cd4f-4b9f-94cc-ef69d95087cb"
}

notice that it only printed the first time.

[agentcore-devx-automation]

Claude Security Review: no high-confidence findings. (run)

[agentcore-devx-automation]

AgentCore Harness Review

Verdict: Looks good

Nice, clean refactor. The move to lazy first‑run persistence in src/index.ts (with set() updating the cache before telemetry emits) means getResourceAttributes() on shutdown still sees the freshly persisted installationId, so telemetry keeps working within the first-run session. The printFirstRunNotice unit test is appropriately scoped and doesn't over‑mock.

One small behavioral note (not blocking):

• src/handlers/config/handler.tsx — coerceValue switches on typeof current against DEFAULT_GLOBAL_CONFIG. Since DEFAULT_GLOBAL_CONFIG.installationId is now undefined, running agentcore config installationId <uuid> will fall through to the default branch and throw Unsupported target type "undefined". Previously the default was a random UUID string, so this path worked. It's a rare command and there was no test covering it before, but if you want to preserve the ability to override installationId from the CLI, you'd need to either treat undefined current-values as strings in coerceValue, or key the switch on the schema rather than the default value. Otherwise consider it intentional that installationId is now effectively read‑only via agentcore config (users can still edit ~/.agentcore/config.json directly).

Also worth considering (optional): if globalConfigAccessor.set() fails on first run, the notice will be re‑shown on every subsequent invocation and telemetry will keep failing schema validation (silently) for the whole session. Current behavior is best‑effort with a warning log, which seems acceptable.

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 97.22%. Comparing base (d304147) to head (bc4bef2).

Additional details and impacted files

@@            Coverage Diff            @@
##           refactor    #2156   +/-   ##
=========================================
  Coverage     97.22%   97.22%           
=========================================
  Files           507      508    +1     
  Lines         33809    33815    +6     
=========================================
+ Hits          32872    32878    +6     
  Misses          937      937           

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[agentcore-devx-automation]

Claude Security Review: no high-confidence findings. (run)

[AlexanderRichey]

Would it be simpler to return isFirstRun in the output here? Would that avoid having to make many of these other changes?