feat: wire observability client to harness and evals

[nborges-aws]

Description

Extend shared observability abstraction to Batch Evaluation and Harness. Plus, add endpoint qualifier support to Runtime observability commands.

• adds log stream reader to the shared CloudWatch client using GetLogEvents
• moves CloudWatch logic hosted in batch eval stream (e.g. pagination, normalization) to the shared CloudWatch client
• resolves Harness resources to their underlying Runtime IDs for observability
• reuse Harness runtime resolution in existing Eval agent resolution
• adds harness logs and harness traces list/get functionality
• adds optional --qualifier flag to Runtime and Harness (falls back to default endpoint)
• updates shared trace output handling and test coverage for CloudWatch, Eval, Harness, and Runtime wiring

Type of Change

• Bug fix
• New feature
• Breaking change
• Documentation update
• Other (please describe):

Testing

How have you tested the change?

• bun run test (2809 pass, 0 fail)
• 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

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[codecov-commenter]

Codecov Report

❌ Patch coverage is 85.20000% with 37 lines in your changes missing coverage. Please review.
✅ Project coverage is 97.01%. Comparing base (831025c) to head (b1ddb37).

Files with missing lines	Patch %	Lines
src/handlers/harness/logs/index.tsx	44.11%	19 Missing ⚠️
src/handlers/harness/traces/get/index.tsx	65.38%	9 Missing ⚠️
src/handlers/harness/traces/list/index.tsx	62.50%	9 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##           refactor    #2182      +/-   ##
============================================
- Coverage     97.09%   97.01%   -0.09%     
============================================
  Files           544      549       +5     
  Lines         37834    38028     +194     
============================================
+ Hits          36736    36893     +157     
- Misses         1098     1135      +37     

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[agentcore-devx-automation]

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

[agentcore-devx-automation]

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

[AlexanderRichey]

Looks like this can't be merged yet?