test: add e2e test for evaluations lifecycle

[Hweinstock]

Description

The evaluations feature (custom evaluators, online eval configs, on-demand evals, pause/resume) is missing e2e test coverage. This PR adds a standalone e2e suite that tests the full lifecycle against real AWS infrastructure.

Also refactor e2e test setup to be build consumable utility functions rather than a single mono-function.

Known limitation: logs evals not included

Online eval log processing is async and the CloudWatch log group (/aws/bedrock-agentcore/evaluations/results/{configId}) was not populated within 8+ minutes of polling across multiple test runs. This makes logs evals assertions unreliable for e2e testing.

Related Issue

Closes #

Documentation PR

N/A — test-only change.

Type of Change

• Bug fix
• New feature
• Breaking change
• Documentation update
• Other (please describe): e2e test coverage for evaluations lifecycle (user stories 2.4, 2.5, 10.1, 10.3, 10.4)

Testing

How have you tested the change?

• I ran npm run test:unit and npm run test:integ
• I ran npm run typecheck
• I ran npm run lint
• If I modified src/assets/, I ran npm run test:update-snapshots and committed the updated snapshots

Verified against dev account (us-east-1). All 6 tests pass in ~4 minutes:

Checklist

• I have read the CONTRIBUTING document
• I have added any necessary tests that prove my fix is effective or my feature works
• I have updated the documentation accordingly
• I have added an appropriate example to the documentation to outline the feature, or no new docs are needed
• My changes generate no new warnings
• Any dependent changes have been merged and published

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[tejaskash]

Looks good. Clean refactoring of e2e helpers and solid evals lifecycle test coverage.