feat: enable CloudWatch Transaction Search on deploy

[jesseturner21]

Description

After a successful deploy with agents, the CLI automatically enables CloudWatch Transaction Search in the target region. This sets up the full observability pipeline: Application Signals discovery, CloudWatch Logs resource policy for X-Ray, trace segment destination to CloudWatchLogs, and configurable indexing percentage (default 100%).

All operations are idempotent and safe to run on every deploy. The setup is non-blocking — failures are logged as warnings and never fail the deploy.

Configuration via ~/.agentcore/config.json:

• Opt out entirely: { "disableTransactionSearch": true }
• Custom indexing percentage: { "transactionSearchIndexingPercentage": 50 }

Changes

• New: src/cli/aws/transaction-search.ts — AWS client wrapper for Application Signals StartDiscovery, CloudWatch Logs resource policy, X-Ray trace destination, and indexing rule configuration
• New: src/cli/operations/deploy/post-deploy-observability.ts — orchestration for the post-deploy transaction search setup with config-based opt-out and indexing percentage
• New: src/cli/aws/__tests__/transaction-search.test.ts — unit tests for enableTransactionSearch
• New: src/cli/operations/deploy/__tests__/post-deploy-observability.test.ts — unit tests for setupTransactionSearch
• Modified: src/cli/commands/deploy/actions.ts — integrated post-deploy step (CLI path)
• Modified: src/cli/tui/screens/deploy/useDeployFlow.ts — integrated post-deploy step (TUI path)
• Modified: src/lib/schemas/io/cli-config.ts — added disableTransactionSearch and transactionSearchIndexingPercentage config options
• Modified: package.json — added @aws-sdk/client-application-signals and @aws-sdk/client-xray

Related Issue

Closes #

Documentation PR

N/A

Type of Change

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

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

E2E verified on account 252624323091 (us-west-2): full deploy with Strands agent confirmed all four Transaction Search components enabled (Application Signals, resource policy, CloudWatchLogs destination, 100% indexing).

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

---

By submitting this pull request, I confirm that you can use, modify, copy, and redistribute this contribution, under the
terms of your choice.