feat: Step inputs override model definition attributes (implicit inputs)

[keeb]

Summary

• Model definition attributes now act as implicit inputs — defaults that step inputs can override
• Eliminates the need for verbose CEL workarounds like ${{ has(inputs.memory) ? inputs.memory : 2048 }} on every overridable attribute
• Applied after CEL evaluation in both the workflow path (execution_service.ts) and CLI path (model_method_run.ts), so expressions resolve first, then concrete input values take precedence

How it works

If a model defines memory: 2048 and a workflow step passes inputs: { memory: 1024 }, the execute function sees memory: 1024. Static attributes are defaults; step inputs override them.

Test plan

• Workflow path: swamp workflow run create-stateful-vm --input '{"vmName":"test-stateful","memory":1024,"cores":1,"diskSize":4}' — VM created with overridden specs (1024MB, 1 core, 4GB) instead of model defaults (2048/2/32)
• CLI path: swamp model method run testVm delete --input '{"vmName":"test-stateful"}' — worked correctly
• Non-overridden attributes retain their evaluated values
• CEL expressions evaluate before input overrides are applied

🤖 Generated with Claude Code

[github-actions]

Review Summary

This PR correctly implements implicit input overrides, allowing step inputs to override model definition attributes after CEL evaluation.

Blocking Issues

None.

Code Quality ✅

• TypeScript strict mode: No any types introduced
• Named exports: Follows the project's export conventions
• The changes are consistent across both paths (CLI and workflow execution)
• Order of operations is correct: CEL evaluation → input overrides → vault resolution
• No security vulnerabilities introduced

DDD Compliance ✅

• The Definition entity's setAttribute() method is an existing pattern in the codebase
• The change appropriately treats inputs as runtime overrides at the application layer

Suggestions (non-blocking)

1. Test coverage: Consider adding a unit test that specifically verifies input override behavior. For example, a test that:

   • Creates a definition with memory: 2048
   • Passes inputs: { memory: 1024 }
   • Verifies the final evaluated definition has memory: 1024

   This would provide regression protection for the new behavior. However, given the straightforward nature of the change and the documented manual testing, this is not blocking.

Verified Behavior

• Step inputs override evaluated attributes after CEL expressions are resolved
• Both model_method_run.ts (CLI path) and execution_service.ts (workflow path) are updated consistently
• Vault expressions are resolved after input overrides, preserving the security model