feat: error messages are not actionable, how to debug CDK synth failures and container build failures?

[ienugr]

Description

When using agentcore-cli, I ran into two issues where the error output was too vague to act on.

Issue 1: CDK synth fails silently

After initialising a new agentcore project and running agentcore memory import, I got:

CDK synth failed: node dist/bin/cdk.js: Subprocess exited with error 1                          

No further detail. The root cause turned out to be that cdk bootstrap had not been run yet. A
clearer error like "CDK environment is not bootstrapped, run cdk bootstrap first" would have
saved a lot of time.

Issue 2: Container build fails silently

Running agentcore dev produced:

container build failed (exit code 1) agentcore                                                  

Again, no log output. Workaround was to run the agent directly (uv run main.py) and skip the
CLI wrapper entirely.

Questions:

1. Where are the full build logs for agentcore dev stored so I can diagnose container build
   failures?
2. Is there a verbose or debug flag for agentcore-cli?
3. Is cdk bootstrap an undocumented prerequisite for all agentcore-cli commands, or only
   deployment-related ones?

Acceptance Criteria

1. Explains where the full logs for agentcore dev container build failures are stored, or how to retrieve them.
2. Confirms whether a verbose or debug flag exists for agentcore-cli, and if so, how to use it.
3. Clearly states whether cdk bootstrap is a prerequisite for all agentcore-cli commands or only a subset, and ideally links to official documentation that mentions this requirement.

Optional: explains the recommended workflow order when setting up a new agentcore project for
the first time (e.g. bootstrap before any other command).

Additional Context

No response