Add update primitive (similar to agentcore configure)

[rhbelson]

Description

While editing agentcore.json is one option, customers leverage the CLI are accustomed to primitives for create, delete and update.

Take adding memory to an existing agent, for an example. Today, you'd have to do something like this:

agentcore remove agent --name personalAgent
agentcore add agent \
  --type byo \
  --name personalAgent \
  --code-location ./app/personalAgent \
  --entrypoint main.py \
  --authorizer-type CUSTOM_JWT \
  --discovery-url $DISCOVERY_URL \
  --allowed-clients $CLIENT_ID \
  --framework strands \
  --model-provider bedrock \
  --language python \
  --idle-timeout 120

Developers will find themselves asking "why do I have to delete the agent to only add it back again?"

Additionally, if I were to update a system prompt in my Strands main.py file provided by the scaffolding, agentcore deploy -y won't pick up that change

Acceptance Criteria

• Change-detection support for agentcore deploy -y (and/or direct code deploy of the existing project files each time)
• Support for agentcore configure primitive (or alternative)

Additional Context

No response