Revamp `agentcore status` to show full project state and pending changes

[notgitika]

Problem

agentcore status currently only shows agent runtime status (deployed/not deployed + runtime state). It doesn't give users a comprehensive view of their project's state, which creates confusion — especially after local changes like agentcore remove that haven't been deployed yet.

Key gaps:

1. No visibility into non-agent resources — memory, identity, and targets are not shown at all.
2. No indication of pending changes — if a user runs agentcore remove agent (which only modifies the local schema), there's no way to tell that the removal hasn't been deployed yet.
3. No deployed resource identifiers — users can't see ARNs or other identifiers for deployed resources.

Proposed Behavior

agentcore status should act as a comprehensive "list everything" command that shows the full project state:

Display all resource types

• Agents
• Memory configurations
• Identity configurations
• Targets

For each resource, show deployment state

• Deployed — show the ARN (or relevant identifier)
• Local only — resource exists in schema but hasn't been deployed yet
• Pending removal — resource was removed locally but the change hasn't been deployed

Track removed resources

To support the "pending removal" state, we need to track what has been removed locally so status can surface it. This likely means extending the local state tracking (e.g., deployed-state.json or a new mechanism) to record resources that exist in deployed state but have been removed from the schema.

Current Implementation

The status command lives in:

• src/cli/commands/status/command.tsx — command registration + rendering
• src/cli/commands/status/action.ts — business logic

It currently reads from:

• agentcore/agentcore.json — project spec
• agentcore/aws-targets.json — deployment targets
• agentcore/.cli/deployed-state.json — deployed state tracking
• AWS Bedrock AgentCore API — runtime status

Design Considerations

• The diff between local schema and deployed state can be computed by comparing agentcore.json with deployed-state.json — resources in deployed state but not in the schema are "pending removal."
• ARNs for deployed resources should come from the deployed state or AWS API.
• Consider a table or structured output format for readability.
• Should work with --target flag to scope to a specific deployment target.