fix(dev): support multiple A2A runtime ports

[notgitika]

Summary

• Allocate A2A development ports from 9000 + runtime index, while honoring an explicit --port for the selected runtime.
• Apply the same port resolution across direct logs mode, terminal UI, web UI, and prompt invocation.
• Map each container's unique host port to its internal A2A port and advertise the reachable host URL in the agent card.
• Pass PORT and AGENTCORE_RUNTIME_URL to CodeZip A2A processes.
• Keep MCP on its framework-required fixed port and retain existing explicit-port conflict behavior.

Closes #1657.

SDK dependency

Container A2A runtimes work independently because each container still binds internally to 9000. CodeZip A2A runtimes require aws/bedrock-agentcore-sdk-python#593 so serve_a2a honors the CLI-provided PORT; that PR is stacked on the A2A v1 migration in aws/bedrock-agentcore-sdk-python#591.

Agent Inspector requires no change: it routes start, invocation, and agent-card requests through the CLI backend by agent name, and the backend stores each runtime's resolved port.

Testing

• npm run build
• npm test (415 files, 5,980 tests passed)
• npm run typecheck
• npm run lint -- --no-cache (no errors; existing warnings only)
• Focused dev-port suite (74 tests passed)
• Prettier and pre-commit checks

[github-actions]

Package Tarball

aws-agentcore-0.24.1.tgz

How to install

gh release download pr-1818-tarball --repo aws/agentcore-cli --pattern "*.tgz" --dir /tmp/pr-tarball
npm install -g /tmp/pr-tarball/aws-agentcore-0.24.1.tgz

[agentcore-devx-automation]

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

[github-actions]

Coverage Report

Status	Category	Percentage	Covered / Total
🔵	Lines	40.32%	15056 / 37335
🔵	Statements	39.58%	16048 / 40537
🔵	Functions	34.43%	2568 / 7458
🔵	Branches	33.76%	10030 / 29708

Generated in workflow #4191 for commit 1e2e21c by the Vitest Coverage Report Action

[agentcore-cli-automation]

LGTM. The port allocation change is well-structured and consistent across the four entry points (CLI --logs, TUI hook, web-UI handleStart, and invoke). A few observations from the review, none blocking:

• Container A2A works standalone (the 9001:9000 port mapping is done at the Docker layer), but CodeZip A2A depends on aws/bedrock-agentcore-sdk-python#593 to actually honor PORT. Worth double-checking that PR merges before/with this one is released widely, otherwise users on the current SDK will see the CLI report port 9001 while the server still binds to 9000.
• The invoke flow now recomputes getDevPort on the client side and uses that to reach the server. If a server auto-shifted off the index-derived port (e.g., 9001 was taken → bound to 9002), invoke against the second A2A runtime will fail the same way it does for HTTP today. Pre-existing behavior for HTTP, but new for A2A. Not blocking.
• getDevPort tests only cover A2A and MCP; a couple of HTTP / null-project cases would round it out, but getAgentPort already has that coverage so it's fine.

No new telemetry needed — agent_protocol is already recorded on the existing cli.command_run emissions. Tests reuse the established spawn/fs mocks at true I/O boundaries. Approving.