docs: add transaction search documentation and post-deploy note

[jesseturner21]

Description

Adds documentation for the transaction search feature and surfaces a user-facing note after deploy when transaction search is successfully enabled.

Documentation (docs/transaction_search.md):

• Explains what the CLI does by default (Application Signals, CW Logs resource policy, trace destination, 100% indexing)
• Documents how to override defaults via ~/.agentcore/config.json (disableTransactionSearch, transactionSearchIndexPercentage)
• Lists required IAM permissions
• Notes the ~10 minute activation delay
• Points users to agentcore traces for viewing traces

Post-deploy note:

• After transaction search is successfully enabled during deploy, a note is displayed: "Transaction search enabled. It takes ~10 minutes for transaction search to be fully active and for traces from invocations to be indexed."
• Surfaces in both the headless CLI (--yes / --json) and the interactive TUI deploy screen
• Adds a notes field to DeployResult for structured access

Related Issue

N/A — improves existing transaction search feature with documentation and UX.

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

All 18 transaction search and post-deploy observability tests pass. Pre-existing failures in deploy.test.ts and deploy-teardown.test.ts (CLI help text parsing) are unrelated and fail on clean main as well.

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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[github-actions]

Coverage Report

Status	Category	Percentage	Covered / Total
🔵	Lines	42.72%	3813 / 8925
🔵	Statements	42.29%	4021 / 9506
🔵	Functions	44.06%	742 / 1684
🔵	Branches	44.78%	2532 / 5654

Generated in workflow #959 for commit 4000ee0 by the Vitest Coverage Report Action

[aidandaly24]

lgtm

tests are failing

code does lgtm